This issue is a variant of Detective Comics (DC, 1937 series) #589 [Direct].
On-sale date from Amazing Heroes #138.
Color credits confirmed by Anthony Tollin.
"Cover" for 16 page insert.
Short paragraphs on the creators of this Bonus Book - Lewis Klahr, Steve Piersall, Dean E. Haspiel, Denis Rodier, Dan McKinnon and Danny Vozzo.