Comic Title: Detective Comics #217
Publisher: DC (National Comics Publications, Inc.)
Address: 480 Lexington Avenue, New York, NY
Cover Date: March 1955
Approx. On Sale Date: January 27, 1955 Copyright Date January 25, 1955
Source: Library of Congress, Periodicals 1955
Until 1958 DC did not report actual on sale dates to the copyright office
The publication dates listed in LoC records are NOT release dates.

Frequency: Monthly
Cover Price: $0.10
Page Count: 32
Editor: Jack Schiff

Title: "The Mental Giant of Gotham City"
Pages: 10

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

Writer: Edmond Hamilton
Penciller: Dick Sprang
Inker: Charles Paris

Reprinted In:
Batman Annual #3 (1962)
Batman Annuals Vol. 1 HC (2009)

Feature Character(s)

• Batman (last appearance in Batman #90; next appearance in World's Finest Comics #75)

Supporting Character(s)

• Robin (last appearance in Batman #90; next appearance in World's Finest Comics #75)

Villain(s)

• The Metal Mob (a gang of thieves; no further appearances)

Other Character(s)

• Barney Barrow (a janitor; no further appearances)

Synopsis:
While cleaning a police laboratory, janitor Barney Barrow is exposed to radiation, causing his brain to grow. Barney becomes a mental giant and puts his brain to use in catching criminals. First he deduces Batman’s true identity; then he blackmails the Caped Crusader into working for him.

Batman initially goes along with Barney to catch the Metal Mob. However, Barney’s methods are extreme and dangerous, so Batman disobeys Barney. Fortunately the effects of the radiation wears off, restoring Barney to normal without recollection of Batman’s identity.