Ken Russell	...	(Director)
Paddy Chayefsky	...	(Writer)
William Hurt	...	Professor Eddie Jessup
Blair Brown	...	Emily Jessup
Bob Balaban	...	Arthur Rosenberg
Charles Haid	...	Mason Parrish, Professor of Endocrinology at Harvard Medical School
Thaao Penghlis	...	Prof. Eduardo Eccheverria at University of Mexico
Miguel Godreau	...	Primal Man
Dori Brenner	...	Sylvia Rosenberg
Peter Brandon	...	Alan Hobart
Charles White-Eagle	...	The Brujo, Hindris Indian
Drew Barrymore	...	Margaret Jessup
Megan Jeffers	...	Grace Jessup
Jack Murdock	...	Hector Orteco
Francis X. McCarthy	...	Obispo (as Frank McCarthy)
Deborah Baltzell	...	Schizophrenic Patient
Evan Richards	...	Young Rosenberg
Jordan Cronenweth	...	Cinematographer

Summary: The main problem with this 1980 science fiction drama is that it is oh-so derivative. However, it is classier than your average Wolf Man rip-off, as Ken Russell directed it and the screenplay it is based on the 1978 novel by Paddy Chayefsky. However, Chayefsky so disliked the finished version of the film, with its preposterous ending, that he asked to have his name removed, with the credit for the screenplay attributed to his pseudonym, Sidney Aaron.
William Hurt, in his screen debut, plays the mad scientist who develops a kind of think tank that regresses him to a primal state. In other words, he enters a meek scientist, but emerges a hairy ape. The film's pacing is part of the problem, as it talks us to death in the beginning, than lapses into more typical fare, disregarding the intellectual aspects of the original material. This film marks the screen debut of Drew Barrymore. --Rochelle O'Gorman