A Scanner Darkly is a science fiction novel by American writer Philip K. Dick, published in 1977. The semi-autobiographical story is set in a dystopian Orange County, California, in the then-future of June 1994, and includes an extensive portrayal of drug culture and drug use. The novel is one of Dick's best-known works and served as the basis for a 2006 film of the same name, directed by Richard Linklater.

Philip Kindred Dick, often referred to by his initials PKD, was an American science fiction writer and novelist. He wrote 44 novels and about 121 short stories, most of which appeared in science fiction magazines during his lifetime. His fiction explored varied philosophical and social questions such as the nature of reality, perception, human nature, and identity, and commonly featured characters struggling against elements such as alternate realities, illusory environments, monopolistic corporations, drug abuse, authoritarian governments, and altered states of consciousness. He is considered one of the most important figures in 20th century science fiction.