Psycho II is a 1982 novel by American writer Robert Bloch. It is a sequel to his 1959 novel Psycho. The novel was completed before the screenplay was written for the unrelated 1983 film Psycho II. According to Bloch, Universal Studios loathed the novel, which was intended to critique Hollywood splatter films. A different story was created for the film and Bloch was not invited to any screenings. Universal suggested that Bloch abandon his novel, which he declined and released anyway to good sales.

Psycho is a 1959 novel by American writer Robert Bloch. The novel tells the story of Norman Bates, a caretaker at an isolated motel who struggles under his domineering mother and becomes embroiled in a series of murders. The novel is considered Bloch's most enduring work and one of the most influential horror novels of the 20th century.