Data courtesy of the Grand Comics Database under Creative Commons license.

Issue Details

Issue	#7
Published	March-April 1957
Cover Price	0.10 USD
Pages	36
Editing	Jack Schiff
Notes	Second appearance of the Challengers of the Unknown. Introduces June Robbins, who later becomes a member.

Cover Details - "ULTIVAC is Loose!"

Characters	Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins; ULTIVAC
Genre	Adventure
Pencils	Jack Kirby
Inks	Jack Kirby
Notes	Second appearance of the Challengers of the Unknown. Introduces June Robbins, who later becomes a member.
Reprinted	in Essential Showcase 1956-1959, The (DC, 1992 series) #nn; in Challengers of the Unknown Archives (DC, 2003 series) #1 (July 2003); in Showcase Presents Challengers of the Unknown (DC, 2006 series) #1

6 page Challengers of the Unknown story "ULTIVAC Is Loose!"

Characters	Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins (first appearance); Felix Hesse (first appearance); ULTIVAC (first appearance)
Genre	Adventure
Script	Dave Wood
Pencils	Jack Kirby
Inks	Jack Kirby?; Roz Kirby (blacks)
Notes	The name ULTIVAC is derived from UNIVAC, considered the first computer. Credits updated 10/06 by Bob Hughes. Previously inker listed as Marvin Stein. Per Stein's conversations with Greg Theakston, he did not ink any Challengers stories.
Reprinted	in Challengers of the Unknown Archives (DC, 2003 series) #1 (July 2003); in Showcase Presents Challengers of the Unknown (DC, 2006 series) #1

6 page Challengers of the Unknown story "Chapter 2: A Challenger Must Die!"

Genre	Adventure
Script	Dave Wood
Pencils	Jack Kirby
Inks	Jack Kirby?; Roz Kirby (blacks)
Reprinted	in Challengers of the Unknown Archives (DC, 2003 series) #1 (July 2003); in Showcase Presents Challengers of the Unknown (DC, 2006 series) #1

6 page Challengers of the Unknown story "Chapter 3: The Fearful Millions"

Genre	Adventure
Script	Dave Wood
Pencils	Jack Kirby
Inks	Jack Kirby?; Roz Kirby (blacks)
Reprinted	in Challengers of the Unknown Archives (DC, 2003 series) #1 (July 2003); in Showcase Presents Challengers of the Unknown (DC, 2006 series) #1

6 page Challengers of the Unknown story "Chapter 4: The Fatal Prediction"

Genre	Adventure
Script	Dave Wood
Pencils	Jack Kirby
Inks	Jack Kirby?; Roz Kirby (blacks)
Reprinted	in Challengers of the Unknown Archives (DC, 2003 series) #1 (July 2003); in Showcase Presents Challengers of the Unknown (DC, 2006 series) #1