Expression/word for reading a book quickly?

devour

dəˈvou(ə)r/

verb gerund or present participle: devouring

read (something) quickly and eagerly. "she spent her evenings devouring the classics"

Source: google search

The only thing I can think of besides speed reading (which Hot Licks already suggested) is "skimmed." For example...

She skimmed through the book.

Type "skimmed through the book" into Google and you'll see many examples.

However, skimming doesn't necessarily denote enthusiasm. On the contrary, some people may skim through books they find boring; they simply want to go through it as fast as they can to find something of interest or determine if they want to read it.

If a person is truly interested in a book but wants to read it quickly, he or she will probably stop skimming and get into speed reading mode.