John Brunner 
Productions of Time [EPUB ebook] 

Until he became an alcoholic, Murray Douglas was one of Britain’s leading actors. Now, after treatment, he’s ready to resume his career, but his first come-back part isn’t exactly what he thought it would be. The idea was to create an avant-garde play where the actors made up the script as they rehearsed. Unusual but hardly frightening. What was frightening was the rest of the cast. Like Murray, they all had some kind of craving. And each of them was given access to whatever had addicted them. It was doubtful if the play would ever entertain the public. But it seemed to entertain the director . . .(First published 1967)