Comic Title: Superman's Pal Jimmy Olsen #138
Publisher: DC (National Periodical Publications, Inc.)
Address: 909 Third Avenue, New York, NY
Cover Date: June 1971
On Sale Date: April 13, 1971 Newsstand Date April 13, 1971
Source: House Ad, Superman #239, Page 59

Newsstand Date April 13, 1971
Source: Etcetera, V1 #2

Copyright Date April 13, 1971
Source: Library of Congress, Periodicals 1971

Frequency: Monthly, with the exception of Feb., May and Nov.
Cover Price: $0.15
Page Count: 32
Editor: Jack Kirby

Title: "The Big Boom"
Pages: 23

Feature(s):
Jimmy Olsen (of Earth-1)

Writer/Penciller: Jack Kirby
Inker: Vince Colletta

Reprinted In:
Jimmy Olsen:Adventures by Jack Kirby Vol. 1 TPB (2003)
Jack Kirby's Fourth World Omnibus Vol. 1 HC (2007)
Jack Kirby's Fourth World Omnibus Vol. 1 TPB (2012)
Jack Kirby's Fourth World Omnibus HC (2018)
Superman's Pal Jimmy Olsen by Jack Kirby TPB (2019)
Absolute Fourth World by Jack Kirby Vol. 1 HC (2020)

Feature Character(s)

• Jimmy Olsen (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in World's Finest Comics #202)

Supporting Character(s)

• Superman (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in Action Comics #399)
• Newsboy Legion (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in Superman's Pal Jimmy Olsen #139)
• Guardian (last appearance in Superman's Pal Jimmy Olsen #136; next appearance in Superman's Pal Jimmy Olsen #139)
• Perry White (last appearance in Superman's Girl Friend Lois Lane #108; next appearance in Superman's Girl Friend Lois Lane #110)
• Gabby, Jr. (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in Superman's Pal Jimmy Olsen #139)
• Tommy (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in Superman's Pal Jimmy Olsen #139)
• Big Words (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in Superman's Pal Jimmy Olsen #139)
• Scrapper, Jr. (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in Superman's Pal Jimmy Olsen #139)
• Flippa Dippa (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in Superman's Pal Jimmy Olsen #139)

Villain(s)

• Simyan and Mokkari (last appearance in Superman's Pal Jimmy Olsen #137; next appearance in Superman's Pal Jimmy Olsen #145)
• Morgan Edge's clone (last appearance in Action Comics #398; next appearance in Superman #237)
• Inter-Gang (last appearance in Mister Miracle #1; next appearance in New Gods #3)
• The four-armed terror (last appearance in Superman's Pal Jimmy Olsen #137; no further appearances)
• Several members of the Homo Usurpus species (last appearance in Superman's Pal Jimmy Olsen #137; no further appearances)

Guest Appearance(s)

• Newsboy Legion (the original team; last appearance in Superman's Pal Jimmy Olsen #136; no further appearances)
• Gabby (last appearance in Superman's Pal Jimmy Olsen #136; no further appearances)
• Big Words (last appearance in Superman's Pal Jimmy Olsen #136; no further appearances)
• Scrapper (last appearance in Superman's Pal Jimmy Olsen #136; no further appearances)
• Tommy (last appearance in Superman's Pal Jimmy Olsen #136; next appearance in Superman's Pal Jimmy Olsen #139)

Other Character(s)

• Terry Dean (last appearance in Superman's Pal Jimmy Olsen #127; no further appearances)
• Miss Conway (Morgan Edge's secretary; first appearance; next appearance in Superman's Pal Jimmy Olsen #139)
• Bernard (an elevator operator; no further appearances)
• Soldiers from the Project (no further appearances)

Comments:
This story is continued from Superman's Pal Jimmy Olsen #137.

Synopsis:
While Superman, Jimmy, and the Newsboy Legion remain trapped in a coccoon, the Guardian and the original Newsboys lead a group of soldiers along the Zoomway intent on stopping the creature which threatens the Project's nuclear reactor. Simyan and Mokkari send more of the creatures to fight the soldiers. Superman finally breaks free, but the four-armed terror has already damaged the reactor beyond repair. To save Metropolis, Superman throws the reactor down a deep shaft. The creatures follow the reactor which inevitably explodes without endangering the city above.