From the Game's Introduction:
Do you like to watch movies or go see plays performed? Have you ever been entranced Have you ever been in a play yourself? Have you ever wished you could, or wished you could be in a movie? Then this is the game for you!
Perform! is a role-playing game of theatrical and movie magic. In it, you, the Director, guide the Actors through the script you have written, while the Actors play their parts to the best of their ability while doing their best to follow your cues.
This book is written with the Director in mind; Actors can still gain a lot from reading this, though.