A Plague of Pythons

From the back cover of the DAW first printing: "Something had seized his mind, something that rode his body like a speed-maniac would drive a stolen car - for he had committed atrocities against his friends and neighbors, he had done unspeakable things - and yet his own conscious mind ahd only stood aside and watched in horror. For a demonic intelligence had taken over inside his skull and left him a helpless observer. He was not unique. It was happening all of the world - society was breaking down in an epidemic of crimes, vicious and senseless, and it would seem as if the world had been invaded by a legion of invisible devils from some interplanetary hell. There had to be a solution, and when at last he found a clue, he set out to pursue it to the bitter end. Frederick Pohl's Demon in the Skull is a revision and upgrading of his A Plague of Pythons, bringing this classic science fiction shocker into the realtime world of 1984 and after..."