Jack Armstrong

John Hart

Jack Armstrong

Rosemary La Planche

Betty Fairfield

Claire James

Princess Alura [Chs. 3-6, 9-11, 15]

Joe Brown Jr.

Billy Fairfield (as Joe Brown)

Pierre Watkin

Uncle Jim Fairfield

Wheeler Oakman

Prof. Hobart Zorn

Jack Ingram

Henchman Blair

Eddie Parker

Henchman Slade

Hugh Prosser

Vic Hardy

The Brass Bullet

⭐ N/A

The Fortieth Door

⭐ 8.0

The Great Secret

⭐ N/A

The Perils of Pauline

⭐ 5.7

King of the Rocket Men

⭐ 5.4