Sphere is a novel written by author Michael Crichton that was published in 1987. The novel was adapted into the film Sphere in 1998. The story follows Norman Johnson, a psychologist engaged by the United States Navy, who joins a team of scientists assembled to examine a spacecraft of unknown origin discovered on the bottom of the Pacific Ocean. The novel begins as a science fiction story but quickly transforms into a psychological thriller, developing into an exploration of the nature of the human imagination.