Comic Title: Action Comics #21
Publisher: DC (Detective Comics, Inc.)
Address: 480 Lexington Avenue, New York, NY
Cover Date: February 1940
Approx. On Sale Date: December 27, 1939 Copyright Date December 24, 1939
Source: Library of Congress, Periodicals 1940
Until 1958 DC did not report actual on sale dates to the copyright office
The publication dates listed in LoC records are NOT release dates.

Frequency: Monthly
Cover Price: $0.10
Page Count: 64
Editor: Fredric Whitney Ellsworth

Title: (The Atomic Disintegrator)
Pages: 13

Feature(s):
Superman (of Earth-2)

Writer: Jerry Siegel
Penciller: Joe Shuster
Inker: Paul Cassidy

Reprinted In:
Superman:The Action Comics Archives Vol. 2 HC (1998)
Superman Chronicles Vol. 3 TPB (2007)
Superman:The Golden Age Omnibus Vol. 1 HC (2013)
Superman:The Golden Age Vol. 2 TPB (2017)

Feature Character(s)

• Superman (last appearance in Action Comics #20; next appearance in Action Comics #22)

Supporting Character(s)

• George Taylor (last appearance in Action Comics #20; next appearance in Action Comics #22)

Villain(s)

• Ultra-Humanite (last appearance in Action Comics #20; next appearance in All-Star Squadron #21)
• Ultra’s henchmen (no further appearances)

Other Character(s)

• Terry Curtis (an atomic scientist; first appearance; next appearance in All-Star Squadron #21)
• Several soldiers and policemen (no further appearances)

Comments:
This story was originally not titled.

Synopsis:
Clark Kent is caught in an explosion, but escapes unharmed. He is taken to the laboratory of Dr. Terry Curtis, who Clark learns, caused the explosion while perfecting an atomic explosive weapon. Ultra, in the body of Dolores Winters, also hears about the weapon and uses his feminine body to get close to Curtis. Ultra then kidnaps the scientist and takes him to his secret headquarters.

Soon, with the weapon perfected and installed on an aircraft, Ultra blackmails the city of Metropolis. Superman stops the plane and rides it back to a volcano which serves as Ultra’s base. Ultra has rigged an explosive device to destroy Metropolis if Superman enters the lab.

In order to rescue Curtis, Superman follows Ultra’s orders to rob a museum of a crown jewel exhibit. The national guard and the police try to stop him, but he obtains the jewels and returns to the volcano. Ultra tries to double-cross him, but Superman destroys his machines, rescues Curtis, and causes the volcano to erupt, destroying the base.