Bob Arctor is a junkie and a drug-dealer, both using and selling the mind-altering Substance D. Fred is a law enforcement agent, tasked with bringing Bob down. It sounds like a standard case. The only problem is that Bob and Fred are the same person. In order to infiltrate the drug ring he hopes to bring down, Fred has had to use Substance D, but Substance D, or "Slow Death, " causes the consciousness to split in two, creating distinct personalities that are entirely unaware of the other's existence. Now, Bob must keep from being caught by Fred, while Fred must keep his suspicious superiors at bay. In this semi-autobiographical novel, Dick looks back on his own drug abuse and his own friends who he lost to drugs. By turns thrilling, mind-bending, laught-out-loud funny, and heart-wrenchingly sad, "A Scanner Darkly" is an award-winning book made into a cult film and may just be Dick's best novel.