This is an excerpt from a letter Kafka wrote to his friend Pollak in 1904, in response to Pollak’s accusation that Kafka never responded to his letters. Kafka excused himself but he had been reading a book that was too important to put down.
I think we ought to only read the kind of books that wound and stab us. If the book we are reading doesn’t wake us up with a blow on the head, what are we reading it for? So that it will make us happy, as you write? Good Lord, we would be happy precisely if we had no books, and the kind of books that make us happy are the kind we could write ourselves if we had to. But we need the books that affect us like a disaster, that grieve us deeply, like the death of someone we loved more than ourselves, like being banished into forests far from everyone, like suicide. A book must be an axe for the frozen sea inside us. That is my belief.