crack a book

crack a book (third-person singular simple present cracks a book, present participle cracking a book, simple past and past participle cracked a book)

1. (informal) To open up one's books, especially in order to study.

   You had better crack the books if you want to have any chance of graduating this year.

The article a is not used exclusively, often it is replaced with the or a pronoun; e.g. "crack the books" or "crack some books". This idiom is also sometimes used without an intermediate determiner, e.g. "Cracking books is not optional in this class."