The Mystery of Mr. X

Robert Montgomery

Nicholas Revel

Elizabeth Allan

Jane Frensham

Lewis Stone

Police Superintendent Connor

Ralph Forbes

Sir Christopher Marche

Henry Stephenson

Sir Herbert Frensham

Forrester Harvey

Joe Palmer

Ivan F. Simpson

Hutchinson

Leonard Mudie

Mr. X

Philip MacDonald

Novel, Adaptation

Lawrence Weingarten

Producer

Adrian

Costume Design

Douglas Shearer

Sound Director

William Axt

Music

Hugh Wynn

Editor

Oliver T. Marsh

Director of Photography

Howard Emmett Rogers

Screenplay

Edgar Selwyn

Director

Merrill Pye

Art Direction

Monckton Hoffe

Additional Dialogue