One of Philip K Dick’s best novels is A Scanner Darkly.
The story is set in a not-too-distant future, and it involves an undercover cop named Bob Arctor, who becomes involved with a dangerous new drug and begins to lose his own identity as a result.
It has recently been made into a brilliant film by Richard Linklater.
The film stars Keanu Reeves, Robert Downey Jr., Woody Harrelson and Winona Ryder.
Here’s a scene from the film, to give you an idea of its tone and style.
If you get a chance, read Philip K Dick’s A Scanner Darkly and watch Richard Linklater’s film version of it. They’re both very good – the novel’s worth reading for its insights into surveillance and its attendant paranoia, and the film’s worth watching for its visual style and its script – and for the superb quality of the acting.