SF Encyclopedia Picture Gallery
Robert J Hogan. The Secret 6: The Complete Adventures (Boston, Massachusetts: Altus Press, 2009) [omni: all titles from The Secret 6: comprising "The Red Shadow", October 1934; "House of Walking Corpses", November 1934; "The Monster Murders", December 1934; and "The Golden Alligator", January 1935: Secret 6: pb/]
Image courtesy of John W Knott, Jr, Bookseller