This is one of 8 tribute issues published this month to honor Julie Schwartz. The two stories inside are based on the cover, a device Julie Schwartz used to inspire his writers.
Cover art is an homage to the cover of Atom (DC, 1962 series) #10 (December 1963-January 1964).
"Bristles" Broome, "Quick" Fox, and "Mad-Dog" Kanigher (mentioned as members of the Broome Gang) are all comic book writers: John Broome, Gardner Fox, and Robert Kanigher respectively. Ed Note is the Earth-One version of Julie Schwartz.