Comic Title: Superman #136
Publisher: DC (National Comics Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: April 1960
On Sale Date: February 4, 1960 Newsstand Date February 4, 1960
Source: House Ad, Action Comics #262, Page 30

Copyright Date February 4, 1960
Source: Library of Congress, Periodicals 1960

Frequency: Monthly, with the exception of March, June, September and December
Cover Price: $0.10
Page Count: 32
Editor: Mort Weisinger

Title: "The Secret of Kryptonite"
Pages: 9

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

Writer: Jerry Coleman
Artist: Al Plastino

Reprinted In:
World's Finest Comics #171 (1967)
Showcase Presents Superman Vol. 2 TPB (2006)
Superman:The Man of Tomorrow Archives Vol. 3 HC (2014)

Feature Character(s)

• Superman (last appearance in Superman #136; next appearance in Superman #136)

Supporting Character(s)

• Lois Lane (last appearance in Superman #136; next appearance in Superman #136)
• Jimmy Olsen (last appearance in Action Comics #262; next appearance in Superman's Girl Friend, Lois Lane #16)
• Perry White (last appearance in Action Comics #262; next appearance in Superman's Girl Friend, Lois Lane #16)
• Lana Lang (in flashback; last appearance in Adventure Comics #251; next appearance in Superboy #18)

Villain(s)

• "Silk" Smith and members of the underworld (no further appearances)

Guest Appearance(s)

• Superboy (in flashback; last appearance in Adventure Comics #251; next appearance in Adventure Comics #171)

Other Character(s)

• Mel Evans (also known as Stanley Halley; a renowned scientist; no further appearances)
• Mayor Perkins (Smallville’s Mayor; no further appearances)

Cameo Appearance(s)

• Jonathan Kent (in reference to the first story of Adventure Comics #251)

Comments:
This story is presented as "An Untold Tale of Superman When He Was Superboy".

How the world learned about Kryptonite is revealed in this story.

Synopsis:
Superman returns to his hometown of Smallville for a celebration of the day he landed on Earth. While there he recalls how the world learned about Kryptonite. When he was Superboy, he was briefly exposed to some in a planetarium exhibit, and a crook named "Silk" Smith witnessed his weakness. The underworld then tried to find out which mineral in the exhibit weakened him. Superboy was able to trick the crooks into believing they were wrong.

Later at the first Superman Earthday celebration, a scientist, Mel Evans gives Superboy a present which is a fragment of Krypton. The fragment is of course Kryptonite, which weakens Superboy. The fragment is taken away, but now the world knows Superboy’s Achilles Heel. The Professor, guilty over his part in the events, changes his name and avoids Superman. At the Superman Earthday celebration in the present, Superman explains that he forgives the scientist and does not blame him for what happened.