What book GOT YOU HOOKED?

It's asking what book interested you from the beginning. The hook is a metaphor, like that of a fisherman, once the fish is hooked it's captured, once the reader is hooked they have no choice but to finish the book.

Compare this to a book you didn't choose to read but had to for an academic course, reading isn't necessarily an enjoyable experience. You're not hooked but are reading out of a sense of duty.