William Shatner

Prof. Stephen Turner

Lynn Carlin

Barbara

Ossie Davis

Reed

Viveca Lindfors

Mrs. Schnagel

Estelle Parsons

Crossland

Roy Poole

Dr. Goodman

Mike Kellin

Mancuso

Richard McKenzie

Mr. Dennison

Fred J. Scollay

Dr. McBride

Stephen Macht

Dahlquist

Lindsay Crouse

Karen

Charles White

Harry Vogel

Gregory Abels

Lab Technician

Robert Burr

Mr. Hughes

Tom Quinn

Bully in Bar

Billie Lou Watt

Mrs. Carol

Michael Howard

Jeff Pomerantz

Professor

Damon Evans

W.T. Martin

Mario, the Waiter

Gary Cookson

Lab Technician

John Travolta

Lab Technician (uncredited)