Notes:
This is the first issue with a DC bullet on cover.
The on-sale date is the publication date reported in the U. S. Copyright Office filing in the Catalog of Copyright Entries, Part 2, Periodicals, New Series, Volume 35, 1940, Number 2. Class B periodical. Copyright number B 449540. The filing states that Detective Comics, Inc. is the publisher and copyright holder.
Synopsis:
While on assignment with Lois Lane as Clark Kent, Superman investigates the conflict between Galonia and Toran and finds munitions manufacturer Luthor behind it. When Lois is kidnapped and taken to Luthor's colossal dirigible, Superman follows and puts an end to Luthor and the war.
Notes:
Radio show begins 2/12/40; Superman #4 on sale 2/15/40. Although this predates Action 23, the Luthor story here comes first. The last panel of this story is an illoed promo ad for the Sandman in ASdventure Comics.