Off-book

Off-book is a theater/acting term meaning that the actor no longer needs the script to rehearse a play; the material is either memorized or improvised. Conversely, on-book means the actor still requires the script in order to rehearse the play.

During the rehearsal project for a play, a date will often be set for the entire cast to be off-book. Actors and actresses are expected to have lines memorized by this date. Some directors will punish performers who fail to be prepared by the deadline.