Fantasy - a story about the world where creatures read books instead of eating

[Daria]

I read this book nearly 10 years ago and I think it was written in 90's.
Different kinds of creatures either read books all day long or look for new ones. The main character is searching for the perfect book.
Hope you can help.

[SamSpayedPI]

Everyone "eats their words" in The Phantom Tollbooth but it was written much earlier, and the quest is to rescue "Rhyme and Reason."