This group is all from the late 50s, many printed right here in Brooklyn, by Rainbow Publishing, B & B Press and Kinney Publishing. They did not exactly run a shop with their name on a shingle... rather, they sold "discreetly" through finer retailers in the Times Square area. Publishers and retailers were constantly dodging the law, in Justin Kent's case (a nom de plume you see on a couple of these), he was held as a material witness for a month after police raids on Times Square shops! There's an interesting article by Jay A. Gertzman HERE.
The format is straight up octavo, 8 1/2 x 5 1/4 inches, or an 8 1/2 by 11 sheet folded, larger than the usual 12mo sized pocket paperbacks that is the format of most pulp fiction, which is mostly where you find Bilbrew's art. These were the early days of illegal porn. Before Ginzberg's Eros. When much the dirty stuff was still being imported from France!
Anyway, hope you dig these illos as much as I do... if I find out more about them at the Long Island Antiquarian Book Fair this weekend in Garden CIty (see sidebar -->) I'll add (or subtract if appropriate) to this post.
Go HERE to see what is said to be a Bilbrew self-portrait...