make book on
make book on something
1. Sl. to make or accept bets on something. Well, she might. But I wouldn't make book on it. Don't make book on my success in this game.
2. Sl. to feel confident enough about something to accept wagers on it. Of course the delivery date is certain. You can make book on it! The work might be done on time, but I wouldn't make book on it.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.