This issue is a variant of Action Comics (DC, 1938 series) #526 [Newsstand].
Direct market editions have an inserted centerfold, on glossy paper and are 40 pages. This contains the Hostess ad, the CBS Saturday morning cartoon line-up and an ad for Monogram models.
Credits for script, pencils and inks confirmed from Julius Schwartz's editorial records, provided by DC Comics.
letters submitted by Bill Curley, David Coakley, Alan Gary Giroux, Tim Wahowske, Matt Kilkelly