So I just finished Book 1. So when is the 2nd book coming out?

We don't know yet.

Back in June, they said they would announce the release date for Book Two shortly after Book One is out - I suspect they need a little more time to take care of any issues people are having with Book One, and then they'll have a better idea about Book Two. If they stick to that plan, we'll probably hear something more within a week or two.

At a guess - based on the progress they've posted to the backers, I'd say 2-3 months from now.

It goes in beta soon, I think they said. So probably in a few months.

Very short took me 3 hours + I was lost 50% of the time.

It took me 7+ hours and I wasn't stuck anywhere. I just visited all places and clicked on everything until I squeezed out every last inch of exposition. And I still haven't checked out all the alternative dialogue options, not to mention that there are two quite different alternate paths that you choose between very early on. I'm now going to start my second playthrough in order to choose different things in conversations and the other path (I expect it will be around 4 hours now that I won't have to click on objects anymore because I'll have seen them all).

I needed around 6-7 hours to finish book 1
... with visiting all areas and trying almost every door in Europolis (although sadly most won't open).

And now I have to wait for another 2 to 3 month for the release of the next book?

WAY TOO LONG!

Should be not more than max. 1 month imho. Or they should release two books at a time

MY positives:
+ I ran in no game breaking bug
+ graphics are breathless
+ atmosphere
+ story (so far)
+ background music
+ at least for me: no performance issues (intel i7 965 3.2 GHz CPU, 8 GB, win 7 64 bit, Radeon R9 270x), all settings on max. with 1920x1080

MY negatives:
- huge lensflare overglows
- pointing the cursor to items sucks sometimes a little bit (but is better than in other games I've played)
- choices to be made in the game are sometimes not very different it seems. Difficulty to choose.
- at least once it happens, than when I ran, I couldn't stop.
- Imho Zoë (graphics) is a little bit to old (she seems more like 30 than 23).
- no recap of the story so far.
- and I definitely miss the music from MAGNET (I don't like the actual in-game songs not so much ...the street musician)
- NO SUN shining^^

To make it clear: the positives weigh much more than the negatives!!!

Edit:
additional negatives (Geman loacalisation only):
- incomplete Geman localisation (only text, no speech)
- text and speech isn't synchron (may be related to imcomplete localisation)
- female NPCs have male voices (at least twice; merchant Chan an female in group right from Miras Pandemonium shop)
- female text lables on male merchants
- Text and language do not match in friar's keep (prision) on injured prisoner. Decision making therefore sucks.

It was pretty engrossing.
I want the next chapter! :-)

Interesting discussion of game length over in the RTG forums.

I spent about six hours in Book 1. So, about half of Dreamfall. About half of almost any adventure game. That time was mostly spent exploring Europolis. If you don't have any fun with that, the Book becomes considerably shorter.

Book 2 will probably drop some time between December and February. Content wise, it will have another new hub which is equally huge as the Europolis one. From the "content" perspective, there really isn't much to moan about.