OK, I'm at a complete loss. Everything I've read says I need to click on my spellbook in my inventory to cast spells, but I can't find a spellbook anywhere. I've started and restarted the game, and nothing. I'm starting to feel like a complete idiot. Where is my spellbook?

Lord British has information regarding your old equipment.

OK, very mysterious, but I guess I know where I need to go from here. Thanks!

When you arrive in Britain and visit him he'll talk about a hidden location in the castle that contains equipment for you to use. This includes a full set of plate armor and a spellbook

:-) That's an answer like the game, thank you! Even if I did not ask the original question, your answer gave a clue ... ... and your answer showed the path :-)

I remembered where that was the moment I read your post. I wonder what important information from college (where I was when I played) was supposed to occupy that space in my head....

There are actually a couple of other spellbooks to be found in the game, but they're in rather hard-to-reach locations if you're just starting out.

Is there a point in having more than one spellbook or no since only the avatar can cast spells which i think is kinda dumb

different spell books that you find might have different spells in them. you can only cast a spell if you have it in one of your spell books. once you're rich enough to buy all the spells you want, it might be more convenient to just have all of your spells in one book so you don't have to think about flipping through multiple of them.

actually, there might be a downside to holding on to multiple spell books: when you buy a spell, it might be difficult to predict which one of your (multiple) spell books the game will put that new spell into. so if you hold onto multiple spell books while going through the game, buying spells, it might increase the fragmentation of different spells being in different spell books.