Not entirely forgotten, I guess, since there are Amazon reviews of it. Here's one comment: "I think this is a real sleeper classic." Here's another: "Read this book to see what happens to Harry. Or don't read it and spare yourself the nightmares. A book for adventurous folk." And another: "It was ok but too weird, . . . ." And of course, this one: "Good thing I got this book from a yardsale, free. The only reason I rate it 1 is because I can't rate it 0."
I tend to agree with the first guy. It's a classic about a brain-damaged guy named Harry who progresses from killing small animals to killing humans. His parents keep him locked up, but one night he escapes. He's killing, people are hunting him to kill him, and it gets pretty gory. Jack MacLane was obviously a real sick-o. As all the reviewers say in one way or another, this is not a book for the squeamish. Or maybe just not for anybody.