Roy Barcroft

The Purple Monster

James Craven

Dr. Cygnus Layton

Dennis Moore

Craig Foster

Linda Stirling

Sheila Layton

Bud Geary

Hodge Garrett

Joe Whitehead

Stewart

Fred Howard

Prof. Crandal

Rosemonde James

Helen

Mary Moore

Marcia

John Davidson

Emperor of Mars

Wheaton Chambers

Prof. Benjamin

Fred C. Brannon

Spencer Gordon Bennet