Comic Title: Justice League of America #30
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: September 1964
On Sale Date: July 23, 1964 Copyright Date July 23, 1964
Source: Library of Congress, Periodicals 1964

Newsstand Date July 23, 1964
Source: Newsdealer Magazine, V19 #7

Frequency: Monthly, with the exception of Jan., April, July and Oct.
Cover Price: $0.12
Page Count: 32
Editor: Julius Schwartz

Title: "The Most Dangerous Earth of All"
Pages: 24

Feature(s):
Justice League of America (of Earth-1)

Writer: Gardner F. Fox
Penciller: Mike Sekowsky
Inker: Bernard Sachs

Reprinted In:
Justice League of America Archives Vol. 4 HC (1998)
Crisis on Multiple Earths Vol. 1 TPB (2002)
Showcase Presents:Justice League of America Vol. 2 TPB (2007)
Justice League of America Omnibus Vol. 1 HC (2014)
Justice Society of America:A Celebration of 75 Years HC (2015)
Justice League of America:The Silver Age Vol. 3 TPB (2017)
Crisis on Infinite Earths Box Set HC (2020)
Justice League of America:A Celebration of 60 Years HC (2020)
Crisis on Multiple Earths:Crossing Over TPB (2021)

Feature Character(s)

• Justice League of America (last appearance in Justice League of America #29; next appearance in Justice League of America #31)
• Superman of Earth-1 (last appearance in Justice League of America #29; next appearance in World's Finest Comics #143)
• Batman of Earth-1 (last appearance in Justice League of America #29; next appearance in World's Finest Comics #143)
• Flash of Earth-1 (last appearance in Justice League of America #29; next appearance in Flash #147)
• Wonder Woman of Earth-1 (last appearance in Justice League of America #29; next appearance in Wonder Woman #148)
• Green Lantern of Earth-1 (last appearance in Justice League of America #29; next appearance in Green Lantern #31)

Guest Star(s)

• Justice Society of America (last appearance in Justice League of America #29; next appearance in Justice League of America #37)
• Doctor Fate (last appearance in Justice League of America #29; next appearance in Showcase #55)
• Black Canary of Earth-2 (last appearance in Justice League of America #29; next appearance in Brave and the Bold #61)
• Starman of Earth-2 (last appearance in Justice League of America #29; next appearance in Brave and the Bold #61)
• Hawkman of Earth-2 (last appearance in Justice League of America #29; next appearance in Justice League of America #37)
• Doctor Mid-Nite (last appearance in Justice League of America #29; next appearance in Flash #159)

Villain(s)

• Crime Syndicate (last appearance in Justice League of America #29; next appearance in Secret Society of Super-Villains #13)
• Ultraman (last appearance in Justice League of America #29; next appearance in DC Comics Presents Annual #1)
• Superwoman (last appearance in Justice League of America #29; next appearance in Secret Society of Super-Villains #13)
• Owlman (last appearance in Justice League of America #29; next appearance in All-Star Squadron #14)
• Power Ring (last appearance in Justice League of America #29; next appearance in Secret Society of Super-Villains #13)
• Johnny Quick of Earth-3 (last appearance in Justice League of America #29; next appearance in Secret Society of Super-Villains #13)

Cameo Appearance(s)

• Snapper Carr (in flashback to Justice League of America #29)

Comments:
Owlman is mistakenly referred to as Batman once in this story.

This story is continued from Justice League of America #29.

Synopsis:
Taking care not to come into prolonged contact with their foes, les they be vibrated into Earth-3, the Justice Society members grapple with the Crime Syndicate. Hawkman defeats Johnny Quick, Dr. Fate overcomes Power Ring, Dr. Mid-Nite gets the best of Owlman, Black Canary beats Superwoman, and Starman outwits Ultraman. However, this time the villains have switched their strategy, and the mere act of claiming victory over their foes shifts the heroes into Earth-3, and they are imprisoned while the Syndicate stages a rematch with the Justice League.

This time each hero faces his counterpart, and defeats him by increasing the villain's powers beyond the point of control. The Crime Syndicate is incarcerated in the transition zone between Earths, and the JSA is freed.