n. The magical object that has made many girls 'chestless' over the years. Refers to females who are 'flat' and have small 'titties,' or breasts due to the undeniable fact that the book has metaphorically fallen on their chest.
Dude, Philly, your girl is fucking tiny. She's got a terrible case of The Book.
Man, shut your ass Swan, your girl got the shit beat of her by The Book.