Comic Title: Action Comics #371
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: January 1969
On Sale Date: November 21, 1968 Copyright Date November 21, 1968
Source: Library of Congress, Periodicals 1968

Newsstand Date November 21, 1968
Source: Comic Reader, #70

Frequency: Monthly (semi-monthly, March)
Cover Price: $0.12
Page Count: 32
Editor: Mort Weisinger

Title: "The Supergirl Best-Seller"
Pages: 12

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

Writer: Leo Dorfman
Artist: Kurt Schaffenberger

Reprinted In:
Supergirl:The Silver Age Omnibus Vol. 2 HC (2018)

Feature Character(s)

• Supergirl (last appearance in Superman #213; next appearance in World's Finest Comics #182)

Villain(s)

• Getaway Gillen and his partner (no further appearances)

Other Character(s)

• Hilda Powell (a librarian; no further appearances)
• Morina (a childhood friend of Kara; in flashback; no further appearances)
• An unnamed judge (no further appearances)

Flashback Appearance(s)

• Supergirl (as a child in Argo City; last appearance in Action Comics #326; next appearance in Action Comics #358)

Cameo Appearance(s)

• Superman (as a balloon)
• Batman (as a balloon)
• Flash (as a balloon)
• Green Lantern (as a balloon)
• An alien from the 7th dimension (in an illustration)

Synopsis:
Librarian Hilda Powell publishes a book about Supergirl. The book contains many secrets that Hilda should not know about. Supergirl questions Hilda and tries to have the book recalled, but her efforts fail.

Supergirl tries to discover how Hilda possesses knowledge of her adventures. When Hilda claims that she plans to publish another book about Supergirl's future life, the Girl of Steel realizes where Hilda got her information. Supergirl briefly moved the library into the future to protect it from an alien attack. She hypothesizes that a person from the future left a biography of Supergirl's life in the library before she returned it to the present.

When Supergirl finds the book, she reads a small section detailing how she prevented a disaster from occurring. Supergirl then acts differently to prevent the disaster. As a result the book from the future ceases to exist, and the knowledge disappears from the memories of all involved.