Paul Frees
Self - Narrator (voice)
Jon Else
Self - Interviewer
J. Robert Oppenheimer
Self (archive footage)
Hans Bethe
Self
Frank Oppenheimer
Self
Haakon Chevalier
Self
Robert Serber
Self
H
Holm Bursom
Self
S
Stirling Colgate
Self
Freeman Dyson
Self
S
Susan Evans
Self
F
Francis Fergusson
Self
Leslie Groves
Self (archive footage)
E
Elizabeth Ingram
Self
R
Robert Krohn
Self
D
Dave MacDonald
Self
Joseph McCarthy
Self (archive footage)
D
Dorothy McKibben
Self
R
Robert Porton
Self
Isidor Isaac Rabi
Self
Harry S. Truman
Self (archive footage)
F
Francoise Ulam
Self
S
Stanislaw Ulam
Self
J
Jane Wilson
Self
R
Robert R. Wilson
Self