OK...

So far so good, but I'm still not 100% sure on a few issues.

The Magic screen for example. Could anyone explain how exactly it works (see attached).
My power base is 10, so if I understand this correctly I get 10 points every day. Out of this I put 4 into my reserves (minus whatever I spend on upkeep), 5 into research and 2 into the spell I'm casting (right?). Why is the total 11 then (4+5+2)?
Also, what is the point of putting spell points into spell casting? I'm casting Hell Hounds at the moment, which have a cost of 40 mana. Having 2 spell points in my third bar, I thought it would take me 20 turns to summon them. But they get summoned immediately since they use spell points from my magic reserve... Why should I allocate any spell points in my third bar then? Can't I just put those points into my first bar (magic reserve?)
And what is Casting Skill n (n)?

Second: cities. In Civilization and Alpha Centauri, I could assign my population to work on certain squares. Not so in this game. Does it mean all squares are being worked on automatically? There is a silver patch above my city, what does it do? Right clicking on it brings nothing.
When I enter surveyor mode, stuff like river tells me +2 food and +10% gold or something. What does the +2 food mean? I have 2 halfling farmers producing 6 food as they should, so it doesn't seem like I'm getting any extra food from those squares, but I'm probably missing something here...
Also is there any point of assigning more farmers than what you need to feed your city and troops? You can't store food, right?

Sorry if these seem stupid. I'm trying to apply my Civilization II and Alpha Centauri knowledge here. Which might not be such a good idea...

I'll be exploring a bit more in the game, but if anyone can shed some light on the above, I'd be grateful.

Questions noted. I'll work on an explanation as soon as I can. I hope to have it up tonight.

Edit: Explanations up! Several other people here can correct me if they see any errors. I know EvilLoynis, UniversalWolf, and TwoHandedSword all haunt this sub-forum on occasion. Also, there is a lot of information on a wiki, including a lot of technical details if you are interested. I'm still happy to answer questions, regardless.

Warning: massive walls of text incoming! [Part 1 of 4]

Some of this is going to be stuff you already know, and I'll try to breeze past that.

-The 4 gems at the top are for enemy wizards, and will be there even if you started with fewer than 4 opponents (extra gems will not become lit or cracked over the course of a game, and gems will be "assigned" from left to right (assigning happens at game start, and wizards will fill in their assigned gem when you meet them)). A cracked gem means a wizard has been either banished (will be able to return upon casting the Spell of Return) or defeated (gone for good this game). Right click on a wizard's gem to see their mirror stats. The black bar below each gem will label the wizard's relationship with you, right click on this bar to get a description and an ordering of relationship labels.

On the right side, in the box labled Overland Enchantments, will be...a list of active Overland Enchantments! *gasp*
The spell names will be in the color of the controlling wizard, and multiple wizards could have the same spell active (ex. Wind Mastery). Right click on a spell to get a spell description. Left click on any of your listed spells to have the option to cancel them (a dialog box appears to confirm).

Along the bottom:
-Your casting skill is listed as X(Y). Y = your base casting skill, while X = the total skill available this turn for casting spells. Every hero that started this turn in your fortress (the town where your wizard's tower is located) will provide half of their casting skill for casting spells on this turn; the X reflects the total extra. Note that heroes won't make a spell 'instant' if your base casting skill isn't high enough to instantly cast anyway (this tripped me up in the "Massive Casting Skill" thread). More on casting skill later.
-Magic Reserve: The amount of mana you have stockpiled in your reserve. There is a hard cap on how much gold and mana you can store at any given time; you can have a max 30k of each (so 30k gold and 30k mana) sitting in your reserves.
-Power Base: The total power income you are earning each turn. This counts things like nodes you control (magic/guardian spirit melds with the node), power produced by city citizens (ex. each High Elf citizen produces 1/2 power point, while each Dark Elf citizen produces 1 power point), structures (ex. Shrines, Alchemist Guild), and the power generated by your wizard's tower (1 point per spell book you have). Note that each Wizard's Guild in a town you control actually produces -3 power; since you have to have an Alchemist Guild (+3 power) to build a Wizard Guild this can't push you into negative power, but it does effectively negate the power provided by the Alchemist Guild.
-Casting: The current spell you are casting
-Researching: The current spell you are researching
-Summon To: This city is where your summoning circle is located. If you summon a creature overland, it will show up in this city. If you use Recall Hero (arcane) or Word of Recall (sorcery), the unit will show up in this city. Use the Summoning Circle spell to move your summoning circle.

The three wands on the middle left are labeled Mana, Research, and Skill. All of your power base is allotted among these three wands. When you get to higher Power Base values, you lose some ability to fine tune the level of each wand (you can only shift several points at a time), but this isn't a big deal. Click on a wand top to "lock" that wand's current value (sort of like you could like one of the Lux/Tax/Science sliders in Civ 2) while adjusting the values. Yes, you can lock two or three wands, which means you can't adjust any of their values without unlocking (click again). The wand's gem will glow while it is locked. Locking a wand can help you tune how you want your power allocated, so you are only adjusting the power between two wands at a time instead of all three. All of these values are used in between turns.
-Mana: How much of your power is converted into mana crystals. Any mana upkeep costs you have are paid first (like taxes in Civ 2), and the rest goes into your reserve. Any mana that is placed in your reserve which would push you over 30k is wasted. This is basically a treasury for your mana crystals.
-Research: How many research points you are generating each turn towards learning the spell you are currently researching. This number reflects more than just power points assigned here; if you have a library in a city, then the minimum value here will be 2, not 0. I think this number accounts for all of your research bonuses: libraries, heroes with the Sage ability, power points dedicated to research, the Sage Mastery retort (wizard ability), etc. are all factored in. Note that any abilities which reduce the research cost are NOT shown here; they will be reflected in the research costs displayed when you consult your apprentice (F3), so Rune Mastery's research cost reduction would not be shown on this screen. Note: if you are not currently researching anything, then any power points spent here are wasted. The game will display "No Spell" instead of a number if you aren't researching anything, so you know to reallocate any power assigned to this slider. Note: any research points spent above what is needed to finish researching the current spell will be wasted, so keep track of how close you are to finishing your current research, and adjust accordingly (while planning, don't forget that your minimum research per turn might not be zero!). If you need 60 research points to finish researching a spell, and you can only get up to 59 total allocated here, then you may as well set the slider to 30 because you'll be taking at least two turns to finish researching it anyway. Find the remaining number of research points needed to finish research by consulting your Apprentice (F3); as you research, the value remaining will go down. You can't change what spell you are researching partway through the process; once you pick a spell to research, you are researching that spell until you learn it.

[To be continued]

[Continued: Part 2 of 4]

-Skill: How many power points you are dedicating to increasing your casting skill. Note: Archmage's power multiplier is NOT reflected by this slider's number. The Archmage's flat bonus of 10 spell skill points is reflected in the Casting Skill value that is displayed below the three wands, but those 10 bonus points are NOT included when calculating how much power you need to allocate via the Skill wand to increase your total casting skill (the bonus casting skill points don't count against you in any way).

Your casting skill starts at 2x(number of spell books), so it can range from 0-22 at game start (0-11 spell books selected). After that, your casting skill will increase as you allocate power to the Skill wand. Technically, power points spent on the skill wand go into a hidden pool, and your spell skill is derived from the total value of this pool. Here's a working formula for increasing casting skill: to increase your casting skill by one point, you need to spend 2x(current skill) via the Skill wand. These points don't have to all be accrued in one turn; the game keeps track of how much you've spent on increasing your spell skill (that hidden pool value). If you have enough power in the Skill slider to raise your casting skill by multiple points in a turn, then it will go up appropriately (no wastage occurs here).

Example: to go from a skill of 10 to a skill of 13, you would need ((10x2) + (11x2) + (12x2)) points allocated to the Skill slider, for a total of 66 points. If you had 66 power allocated to Skill, you would jump straight from 10 to 13 in one turn.

Your casting skill shows two things:
1) How much mana you can channel into casting spells overland each turn. If your casting skill is 20, then you can cast a spell that costs 20 mana (or less) in a single turn (instant). A spell that costs 100 mana would take 5 turns to finish casting. If you finish casting a spell without using up all of your casting skill allotment for that turn, the remainder can be channeled into a new spell. So if your skill is 20, then a spell that costs 110 mana would take 6 turns to complete, and on that 6th turn you could then instant cast a spell that costs 10 mana (or start a spell that costs more). If you have 100 spell skill, you could instantly cast 10 spells that cost 10 mana each, or 2 spells that cost 50, or some other combination of costs up to 100 before you had to wait for next turn's allotment. Except for this specific carry-over, you can't "store" spell skill across turns. If you stop a spell midway, you lose all progress (and mana) spent on that spell thus far (even if you immediately start casting the very same spell).
2) How much mana you can channel into casting spells during each combat (ignoring the mana cost range penalty multiplier). At the beginning of each combat, you have a skill allotment equal to your casting skill for casting spells in that battle. As you cast in that battle, the allotment decreases (possibly restricting your options as it gets smaller). Depending on how far from your capital the battle takes place, there may be a range modifier on the actual mana cost of the spells you cast (0.5x min, 3x max; the farther the battle from your wizard tower, the higher the multiplier, and any battle on the other plane is 3x). Regardless of the actual mana cost, only the base casting cost of the spell is deducted from your remaining skill allotment. So there are effectively two possible caps on your spell casting in combat: how much skill you have, and how much mana you have. Note: battles at your fortress have a 0.5x range multiplier, so they actually cost half of the usual mana (though skill cost remains the same), and there is a bug in the way the game handles this. It decides how much mana you have available for casting spells in combat by calculating [Current Mana/range multiplier] at the start of battle (your actual mana reserve value isn't altered by this calculation). Therefore your mana reserve is considered doubled when this calculation is run for a battle at your fortress; if you have a lot of mana in reserve (starts becoming a problem somewhere in the 16k range), the variable overflows and the game thinks you don't have any mana for casting spells in the battle. This particular bug is fortress specific; just be aware it exists.

Note that spell skill for combat is determined independently for each combat; it doesn't matter how much skill you used in a previous battle when calculating for the next battle (even if they occur during the same turn). Whether you fight 50 battles in a turn, or just 1, you'll have the same skill allotment at the start of each of those battles.

[To be continued]

[Continued: Part 3 of 4]

Example time! From what you've said earlier, I'm assuming you are using the basic Tauron setup, with 10 spell books in Chaos and the Chaos Mastery retort (wizard ability). My comments will reflect this assumption.

Your Power Base to allocate among the three wands is 10. Judging from the city screen shot, all your power is currently coming from your fortress (you have 10 spell books, so your fortress generates 10 power points per turn; if you find another spell book, your fortress will start providing 11 power per turn). If you build a shrine, that will also start adding a power point per turn. If you then add a temple. you'll be making 13 power per turn (10 fortress, 1 shrine, 2 temple). All this power is always divided among the 3 wands.

-Mana: As you said, 4 points minus upkeep costs goes into your reserve. Just like taxes in Civ 2, if you don't generate enough to pay for everything, your reserve will start shrinking. Assuming there is only one hell hound unit in that stack I see in the city screen, you are likely storing 3 mana per turn (4 income - 1 upkeep). Note that when you are casting spells across turns, the mana spent on casting the spell is also deducted from your income (and then from reserve (if possible) to cover the rest of the mana you are able to channel because of your casting skill value). If you don't have enough mana from [income + reserve] to cover all of the mana you can channel for your spell skill, then you'll spend as much mana as is available and casting will be delayed while you come up with more mana. If you are casting spells while running a negative income (more expenses than income), then be careful that you don't run out of mana; some active spells might get canceled for failure to pay upkeep.
-Research: You are earning 5 research points per turn. 4 probably come straight from power, while Chaos Mastery probably provides that 5th research point. Note that Chaos Mastery is lowering the research cost of your Chaos spells in addition to providing a research bonus while you are researching a Chaos spell. Once you finish that library your town is building, the library will start providing 2 research points per turn regardless of how much power you allocate to the Research Wand (and regardless of what you are researching. By contrast, Chaos Mastery only provides a research point bonus while researching Chaos spells).
-The two points in the Skill wand are working to increase your casting skill (the value of which is indicated below the wands). It is the casting skill value that actually determines how much mana you can spend each turn to summon those hell hounds, while mana reserve is the raw currency spent to do the summoning. Your casting skill is 20, so it takes 2 turns to summon a 40 cost unit of Hell Hounds. As power spent on the Skill slider increases your casting skill, you'll be able to spend more mana per turn on summoning hell hounds, thereby getting more of them sooner (this is why you want to spend power on that third slider, to cast bigger spells faster). However, if you check your spell book in game, you'll see that each unit of Hell Hounds only takes 22 mana (and casting skill) to summon in this game (right clicking on the spell displays the default mana/upkeep costs of 40/1). Chaos Mastery is reducing the casting cost of that Chaos spell, and you get some additional discounts in research and casting cost of chaos spells because you have a large focus in Chaos spell books.

[To be continued]

[Continued: Part 4 of 4]

You don't assign your people to work squares in this game; your city always gets the benefits provided by all tiles in the city radius (so if there are two different gold mines in your city radius, you get the bonus from both even with a size 1 city). The city radius is the same cross shape as for the civ games (with Civ 1 being the direct equivalent, since it uses the same display for tiles).

If you bring up your Surveyor (F1), you can mouse over various tiles to see what they provide (ex. a grassland always provides 1.5 food, while a mountain always provides +5% production). The silver stuff in the hills just north of your city is actually the mineral Silver; it provides +2 gold per turn. There are a number of different tile bonuses, and the surveyor will indicate the name of each bonus and what it does (numerically) when you survey it. The surveyor can also indicate the (approximate) max size a city can reach on any given tile (it doesn't take into account buildings you may be able to build, like the granary or forester's guild). The surveyor will indicate if a city can't be built in a particular location and the reason for the block.

Note that if cities overlap their city radii, then the overlapped tiles only provide half of their value to each city (whereas in Civ 2, only one city could work the tile and it got the whole benefit). So if a tile with silver is being utilized by two cities, each city only gets +1 gold from the silver vein. Note that the improved unit weapons provided by access to Mithril or Adamantium are unaffected by this halving rule; a city just needs the mineral in its city radius and a completed Alchemist Guild in order to make weapons from the special mineral. Two properly placed cities can produce adamantium equipped units from a single adamantium mineral vein, though each city only gets +1 power from the vein.

For this paragraph, when I say "potential food", I'm talking about the food values that tiles in the city radius provide, as well as food provided by city buildings (ex. granary), NOT the food actually produced by the farmers of the city. Potential food affects the max size of the city. The more potential food available from the surrounding tiles, the larger the city can become; a city surrounded by grasslands will have a higher max size than a city surrounded by mountains. Potential food also affects how fast the city will grow; more potential food means the city will grow faster as well as having a higher max population. Note that there is a hard cap of 25 pop for any city, regardless of available potential food.

One more thing the potential food affects: how much actual food your farmers can produce. I'm not sure about the specifics, but if there is a lot of potential food available, then you can assign more pop as farmers that are efficient. There is some sort of cap on how much food your farmers can produce, and after a city reaches that cap each extra pop assigned as a farmer will only produce one food. The cap is related to the total potential food available to the city; like I said, I'm not very sure about the specifics. When you need extra food, and you see that assigning extra farmers is only adding one food per farmer, then start using other cities to get the extra food. Note that when farmers are making 1.5 food, the .5 is rounded down, so you will often have a case where 2 extra farmers will net you 3 extra food; adding the first farmer may add only 1 food, while adding the second farmer will add 2 food (then the cycle rinses and repeats). Watch for this to avoid some waste.

Each city can only be fed by itself, and it will try to lock enough citizens as farmers in order to feed itself. Extra food produced beyond that will go to feed your units. You can't store any excess food, but each 2 food you have in excess of required unit maintenance each turn is automatically sold for +1 gold that turn. If you have 10 extra food being produced beyond what you need to feed your troops, then you'll make +5 gold that turn. Before turning everyone into farmers, remember that farmers don't generate much production to build things in the city.

[End of wall of text]

Thank you Bookwyrm. Very much appreciated and +1 to all posts.

I hope I didn't sound too dumb here. I did read the manual, but it's much more easier to understand from you text with your numerical examples.
The fact that I could summon hell hounds in 1 turn had me especially baffled. But from what you wrote it's now all clear. So I get +30% reduction from 10 books, +15% reduction from Chaos mastery, meaning cost of my chaos spells is almost halved. Sweet.

So if I understand correctly, food from farmers feeds city and units, while "potential food" from tiles affects population growth, size and (as well as a cap on the food farmers produce efficiently). Just a question then: in Civ you could see how many turns you need for your city to increase in size (so you could see whether it's good to wait a turn before building this Settler unit for example). Is such a thing possible here?

Also, how do you get extra spell books as the game progresses? The link you gave mentions up to 13, but I couldn't find anything in the manual about getting new ones.

Ooh, ooh, I got this.

Spell books and retorts of wizard skills are among the potential rewards for conquering temples and nodes. In general, the harder such a site is to conquer, the more likely it will have been set up to offer such a reward. As a consequence, most such sites will be found on Myrror.

Protip: Get into the habit of saving before tackling temples and untapped nodes. Spell books and retorts are interchangeable, so if a site does offer one up, you could choose to reload in order to try for something different. The selection is determined by the type of site, so chaos nodes (for example) are biased toward Chaos spell books, while temples/dark temples are more likely to give you Life/Death.

If a site offers up two spell books, it's also possible to get one each of two different types, or one spell book and a retort, or a single retort of a skill that would've required two picks (such as Warlord, Famous or Infernal Power).

There is a hard cap on the number of spell books and retorts you can have, including the ones you started with; IIRC, it's 13 spell books and 6 skills. (Note that two-pick skills do NOT count as two retorts, so you could be a Warlord and still have room for five more skills.)

Also note that while you can never have both Life and Death spell books, there are no such restrictions on found retorts: you could get Node Mastery, Sage Master or even Nature Mastery without having a single Nature spell book. You could even get Divine Power without any Life books, although that would be pretty useless if you did.

Last but not least, if you get one or more spell books of a college you don't already have, you can start trading with or conquering the other wizards to get all the spells they may know of that type — subject to the usual restrictions, such as needing two spell books to learn any Rare spells, and three to acquire Very Rare ones.

Thanks!

(I'm happy I started this on Intro difficulty).

There is a bar on the upper left that shows your citizen icons (indicating whether each is a farmer, worker, or rebel). Just above that bar, on the left, is the name of the race that populates that city (the citizens of each race also look unique). Just above the bar on the right side is the word Population. Next to the word is the current population in thousands, along with progress towards the next pop change and the per turn population change in parenthesis. If a "Population Boom" or a "Plague" (two possible random events) are affecting a city, they will be noted somewhere in this same line above the citizen display.

Using your city screen shot, you have Population: 4,880 (+110).
-You have 4 citizens (each full thousand provides one citizen).
-You have 880/1000 towards your next citizen.
-You earn 110 units towards that next citizen each turn.
-With 880/1000 and +110, it will take two turns to get your 5th citizen.

Any overage beyond what is needed to reach 1000 will be wasted. This mostly comes up when you are building housing to increase growth rate; you can tweak the extra growth from housing by making more or fewer workers into farmers.

Note that you can have a negative growth rate. Population: 4,050 (-100) will lose one citizen next turn. Usually some magic or something has to come into effect (or leave effect) for this to be an issue. When your city reaches its max size, it will usually just stop growing.

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TwoHandedSword covered the extra books pretty well. The short version is that you can find extra spell books and/or retorts as treasure after beating lairs or nodes. As some of the best treasures, the guardians will be fierce (Great Wyrms, Sky Drakes, etc.) and probably numerous, so be warned. Weakly guarded nodes/lairs will not contain extra spell books or retorts.

In any given game, you can only have 13 total spell books, and 6 total retorts.

Update: Met 2 wizards already. One seemed weak (both did actually; I guess that's what I get for playing Intro) so I decided to attack him, which brings me to my next question:

How can you tell which of the 2 is it? After attacking the city I got a "you defeated X" animation. Is he banished, or was that the only city he had?

By the way, Chaos Spawn is amazing!!! Can tak out mellee armies all by himself. Needs help vs sprites (and I suppose other ranged units) since he could be dead before reaching them. Might summon a few more of him...

I have a game started on Normal, 4 opponents, small land size and powerful magic. It's also too easy. My opponents have done a poor job of expanding. Ariel started on the same island as me which is why she hasn't expanded. I did restart this game from the start once as had far too many next turns with a mana income of 1. It also took me quite a few turns to realize how to crack the powerful nodes.

One thing I didn't see mentioned is on the city screen if you click on the left side gold coins it will show you the gold maintenance costs while on the right shows you your gold income. Similar for the other resources.

Oh, be sure to run install.exe, switch to General Midi and use a soundfont for superior music. It's worth it.

Actually, you can get the benefit of Divine Power even if you have Death spell books. Infernal Power is similar. The 4 Life/Death book requirement is just for picking it as a starting retort. Just note they don't give the same sorts of bonuses as Nature/Chaos/Sorcery Mastery.

When a wizard is either defeated or banished, you'll see a mini cut scene of the wizard surrendering to the conquerer (including if a CPU does it to another CPU). The text of the scene will indicate which event occurred (so you would see something like "Tauron Banishes Ariel" or "Tauron Defeats Ariel" depending on which it was). If that was the last city the wizard had, they do not have the option to try and cast the Spell of Return. If they still control other cities, they might decide to try and cast the Spell of Return (I think it depends on how much mana they have stock piled). If the wizard has other cities, but accepts defeat, then all of their other cities turn neutral.

A wizard is eliminated if they have no other cities. If you banish an opponent, then take their last city before they finish the Spell of Return, you'll see the cutscene where you defeat that wizard even though the wizard (by the lore) doesn't have a corporeal form at that time.

If you've met a wizard, but you aren't sure if that wizard has been defeated, then check your Cartographer (F2). If the wizard's name and flag color show up, they aren't defeated yet. If you haven't met a wizard, you'll just have to keep exploring. Cast the spell Awareness when you get it, and you'll be able to see all cities that are currently on the map. You don't need to maintain it afterwards; while it is active, any new cities that are planted will be revealed, but there probably won't be that many new cities by the time you can cast the spell. If you are good at scouting (magic spirits are great for this in the early game), you may not need to cast the spell at all because there is no fog of war and cities are always displayed in any area that you've explored (even if settled long after you've left that area).

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Chaos Spawn are pretty sweet in melee combat, with all those gaze and touch attacks. Their biggest issue is probably their speed; they move pretty slowly so ranged units can tear them apart. That Doom Gaze is just straight damage: no attack rolls, no defense rolls, no resistance, just "Here, take this damage". The Doom Bolt spell is pretty awesome for the same reason, since it just hands out 10 damage with no reply and very little way to avoid it (Magic Immunity perhaps being the only thing).

Oh, and while I'm thinking about it: Outposts. Outposts are sort of like cities, but not really.

When a settler "builds" a city, the settler is consumed and an outpost is created. An outpost stage is sort of a size 0 city. If you right click on an output, you'll just see a box for any active city enchantments and 10 little houses, some of which are colored. The outpost becomes a size 1 city if they all get filled in, and the outpost is abandoned if they all empty (a given house will either be colored in or greyed out, no partial fills). Having more potential food available tends to make the little houses color faster, but there is no guarantee; outposts are rather wonky in settling down. One turn there may be 5 little houses, then the next 8, then the next 3, then the next turn it may turn into a size 1 city. City enchantments that bring positive growth (Gaia's Blessing, Stream of Life) help the outpost grow into a city.

Capturing an opponent's city is an instant declaration of war, and I think even attacking an opponent's city is a war declaration (not as sure about this one). Attacking their units that aren't in a city isn't necessarily going to cause them to declare war, but it certainly won't make them happier with you.

Outposts, however, can be invaded with NO diplomatic penalty (if empty; I'm not as sure about if they have a garrison (I suspect it would just count as if you had attacked the units in the field)). You can't ever capture an outpost (it is automatically destroyed if successfully attacked), but you can destroy it so it can't grow into a city. If you see an enemy outpost, take it if you can. If you need a few turns to travel to it, make sure to check that it is still an outpost before you actually enter it! (I've started a few wars on accident this way, because I forgot to check). If you see an enemy settler wandering around, and you have a spare unit, have the unit follow the settler until it creates an outpost and you can go ahead and destroy the outpost right then. This is an easy way to stunt the growth of enemy wizards.