Kirk Alyn
Inspector David Worth
Rosemary La Planche
Laura Keith
Roy Barcroft
Spade Gordon
Carol Forman
Nila
James Dale
Agent Steve Evans
Bruce Edwards
Prof. Paul Williams [Chs. 1-6]
James Craven
Prof. James Clayton [Chs. 1, 10-12]
Dave Anderson
Porter [Ch. 9]
