"By his wife, Joan Paisnel." Edward Paisnel, aka the titular Beast of Jersey, "terrorised the island for eleven years" before his 1971 conviction for sex offenses against young children. The cover art does seem faintly ridiculous until you remember that Paisnel actually wore this weird rig in "his Hyde moments."
This 1981 edition of the rare paperback is in very nice shape: some rubbing to the bottom edges of the covers, and page toning -- not to mention the closeness of the kerning -- as well as a few spots on the flyleaf. But the spine is uncracked and the pages are firm.