Ubik is a 1969 science fiction novel by American writer Philip K. Dick. The story is set in a future 1992 where psychic powers are utilized in corporate espionage, while cryonic technology allows recently deceased people to be maintained in a lengthy state of hibernation. It follows Joe Chip, a technician at a psychic agency who begins to experience strange alterations in reality that can be temporarily reversed by a mysterious store-bought substance called Ubik. This work expands upon characters and concepts previously introduced in the vignette "What the Dead Men Say".

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.