Comic Title: Doom Patrol #91
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: November 1964
On Sale Date: September 3, 1964 Copyright Date September 3, 1964
Source: Library of Congress, Periodicals 1964

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

Notes:
The cover logo changes as of this issue.

Title: "Mento -- the Man Who Split the Doom Patrol"
Pages: 24

Feature(s):
Doom Patrol (of Earth-1)

Writer: Arnold Drake
Artist: Bruno Premiani

Reprinted In:
DC Special Blue Ribbon Digest #19 (1982)
Doom Patrol Archives Vol. 2 HC (2004)
Showcase Presents the Doom Patrol Vol. 1 TPB (2009)
Doom Patrol:The Silver Age Omnibus HC (2017)
Doom Patrol:The Silver Age Vol. 1 TPB (2018)

Feature Character(s)

• Doom Patrol (last appearance in Doom Patrol #90; next appearance in Doom Patrol #92)
• Chief (last appearance in Doom Patrol #90; next appearance in Doom Patrol #92)
• Robotman (last appearance in Doom Patrol #90; next appearance in Doom Patrol #92)
• Elasti-Girl (last appearance in Doom Patrol #90; next appearance in Doom Patrol #92)
• Negative Man (last appearance in Doom Patrol #90; next appearance in Doom Patrol #92)

Supporting Character(s)

• Mento (Steven "Steve" Dayton; next appearance in Doom Patrol #92)

Villain(s)

• Garguax (an exiled criminal; next appearance in Doom Patrol #96)
• The Plastic Men (androids of three types created by Garguax; destroyed in this story; next appearance in Doom Patrol #97)

Comments:
Part 2: "Terror of the Android Master"
Part 3: "Fortress in the Stratosphere"

Mento apparently possesses two different styles of psychokinetic helmets, each of which he wears in this story. He also has several uniforms, each of slightly different design, as his costume changes slightly in his subsequent appearances. He adopts an entirely new helmet and costume in Doom Patrol #104.

Synopsis:
Steve Dayton, the world's fifth richest man and a professor of research psychology, uses a special helmet to give himself psychokinetic powers which he uses as a new super-hero called Mento. After upstaging the Doom Patrol, he begins to romance Elasti-Girl. Meanwhile, a group of strangely powered androids appears and begins committing seemingly senseless acts of destruction across the country. The Chief traces them to a fantastic floating city which is the base of Garguax, an alien invader who is using Earth to test his super-weapons before returning to conquer his home planet. Mento infiltrates Garguax's operation before the Doom Patrol can arrive, only to be captured and brainwashed into battling the Patrol. Freed of Garguax's domination, Mento teams up with the Doom Patrol to destroy the androids and wreck the alien base. Garguax appears to perish with his creations.