I’ve never read it, but when I was growing up, this was a VERY big thing:
All of the covers had little cutouts, and you’d flip them open in the hopes that the face behind the metallic sunburst peep hole was attached to a naked body, or at least a well-hung centaur.
More often than not, it just turned out to be a seamy trompe l’oeil photo painting of a lady sitting in a chair really dramatically.