Comic Title: Superboy #58
Publisher: DC (National Comics Publications, Inc.)
Address: 480 Lexington Avenue, New York, NY
Cover Date: July 1957
Approx. On Sale Date: May 23, 1957 Copyright Date May 21, 1957
Source: Library of Congress, Periodicals 1957
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, with the exception of Feb., May, Aug., and Nov.
Cover Price: $0.10
Page Count: 32
Editor: Mort Weisinger

Title: "The Great Kryptonite Mystery"
Pages: 8

Feature(s):
Superboy (of Earth-1)

Writer: Jerry Coleman
Penciller: Curt Swan
Inker: Ray Burnley

Reprinted In:
Superman #227 (1970)

Feature Character(s)

• Superboy (last appearance in Superboy #58; next appearance in Showcase #9)

Supporting Character(s)

• Jonathan Kent (last appearance in Superboy #58; next appearance in Adventure Comics #238)
• Martha Kent (last appearance in Superboy #58; next appearance in Adventure Comics #238)

Villain(s)

• Ten Kryptonian criminals (no appearance)

Other Character(s)

• Various military personnel (no further appearances)

Comments:
Superboy learns that ten Kryptonian criminals were exiled in a space satellite due to arrive on Earth in 15 years. These criminals must have been exiled before the discovery of the Phantom Zone.

Synopsis:
Superboy begins deliberately exposing himself to Kryptonite meteors and collecting them in a secure vault. He refuses to tell anyone why he is hurting himself. The continued exposure causes the Boy of Steel to become ill and his powers weaken. After collecting several such meteors, Superboy hides the vault of Kryptonite on the ocean floor. He explains to his foster parents that he hoped to build up an immunity to the Kryptonite meteors, so that he could use them later against ten Kryptonian criminals due to arrive on Earth in 15 years.