"The owner of a coal mining operation, falsely imprisoned for fratricide, takes a drug to make him invisible, despite its side effect: gradual madness."
Cedric Hardwicke
as Richard Cobb
Vincent Price
as Geoffrey Radcliffe
Nan Grey
as Helen Manson
John Sutton
as Dr. Frank Griffin
Cecil Kellaway
as Inspector Sampson
Alan Napier
as Willie Spears
Forrester Harvey
as Ben Jenkins
Ernie Adams
as Minor Role (uncredited)
Jimmy Aubrey
as Plainclothesman (uncredited)
Walter Bacon
as Fight Spectator (uncredited)
Billy Bevan
as Jim (uncredited)
Clara Blore
as Woman (uncredited)
Stanley Blystone
Matthew Boulton
as Policeman (uncredited)
Ed Brady
Chet Brandenburg
as Miner at Colliery (uncredited)
Louise Brien
as Griffin's Secretary (uncredited)
Charles Brokaw
Jean Brooks
Tom Coleman
Frank Coletti
Harry Cording
as Miner (uncredited)
Paul England
as Detective (uncredited)
Rex Evans
as Constable Briggs (uncredited)
Mary Field
as Passerby at Willie's House (uncredited)
Edward Fielding
as Prison Governor (uncredited)
Raoul Freeman
Mary Gordon
as Cookie (uncredited)
Sidney Grayler
Kit Guard
Frank Hagney
as Bill (uncredited)
Bobby Hale
Barry Hays
Frank Hill
Leyland Hodgson
as Chauffeur (uncredited)
Hugh Huntley
as Secretary (uncredited)
George Hyde
as Miner at Radcliffe Colliery (uncredited)
Ellis Irving
Boyd Irwin
Dick Johnstone
Colin Kenny
George Kirby
Bruce Lester
as Chaplain (uncredited)
George Lloyd
Jack Low
Edmund MacDonald
William Newell
Frank O'Connor
as Constable at Coal Train (uncredited)
Alexander Pollard
as Footman (uncredited)
Frances Robinson
as Clinic Nurse (uncredited)
Robert Robinson
Ivan F. Simpson
as Mr. Cotton (uncredited)
Harry Stubbs
as Constable Tewsbury (uncredited)
Denis Tankard
Cyril Thornton
David Thursby
as Bob (uncredited)
Crane Whitley
Eric Wilton
as Fingerprint Expert (uncredited)
Joe May
Director
Curt Siodmak
Screenplay
Lester Cole
Jack Otterson
Art Direction
Vera West
Costume Design
Frank Skinner
Original Music Composer
Hans J. Salter
Milton Krasner
Director of Photography
Russell A. Gausman
Set Decoration
Story
H.G. Wells
Characters
Frank Gross
Editor
John P. Fulton
Visual Effects
Cedric Belfrage
Additional Writing
Ken Goldsmith
Associate Producer
Phil Karlson
Assistant Director
Martin Obzina
Bernard B. Brown
Sound Supervisor
William Hedgcock
Sound Engineer
Cleo E. Baker
David S. Horsley
Special Effects
Charles Previn
Music Director