be an open book

be an open book

 
1. if a person's life is an open book, you can discover everything about it because none of the details are kept secret Like many film stars, he wants to keep his private life private - he doesn't want it becoming an open book.
2. if someone is an open book, it is easy to know what they are thinking and feeling Sarah's an open book, so you'll know right away if she doesn't like the present you've bought her.
See also: book, open
References in periodicals archive ?
OAKLAND - The Lakers' lives will soon be an open book.