I'm reading a book right now that has a spell book as a minor character. I don't think I've laughed out loud from reading a book this much in a long time. There is just something about this spell book that tickles my funny bone. The series is Mage Errant by John Bierce. I'm on book 4.
Spoiler ahead. (I tried making it disappear like a nice spoiler, but it didn't work easily. So I just put it far away.)
First, the book is found eating some coals because it wants to spit them out at children. It thinks this would make it into a dragon.
Later the book is found trying to become a parrot. The nearby parrots tolerate it.
It doesn't know how to apologize, so it keeps dumping slimy fish on someone.