[1] 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.

A group of scientists (psychologist Norman Johnson, mathematician Harry Adams, zoologist Beth Halpern, astrophysicist Ted Fielding, and marine biologist Arthur Levine), along with U.S. Navy personnel, travel to a deep sea habitat at the bottom of the Pacific Ocean, where a 1⁄2 mile (800 m) long spacecraft has been discovered.

Reasoning the ship's future builders were apparently unaware that it had already been found in their past, Adams becomes convinced that the team will not survive to report their discovery.

Meanwhile, on the surface, a Pacific cyclone forces the supporting Naval ships to evacuate, trapping and isolating the scientists on the ocean floor for five days.

At this point, members of the team start to die in various attacks by giant squid, and the dwindling band of survivors struggle in their dealings with the unthinkably powerful, childlike, and temperamental alien entity.

Johnson hypothesizes that the sphere is an object which allows a person's subconscious thoughts to manifest in reality, and Harry Adams has acquired the power through entering it.

Inside the sphere, he finds a large sea of translucent "foam," and has a conversation in his thoughts with some sort of entity that speaks in cryptic riddles, who eventually tells Johnson that the greatest power humans possess is the ability to imagine things.

[2]The book was made into the film Sphere (1998), directed by Barry Levinson, with a cast including Dustin Hoffman (Norman Johnson, renamed Norman Goodman), Samuel L. Jackson (Harry Adams), Peter Coyote (Harold Barnes), Liev Schreiber (Ted Fielding), and Sharon Stone (Beth Halpern, renamed Beth Halperin).

It was rated 12% by Rotten Tomatoes with the consensus opinion: "Sphere features an A-level cast working with B-grade material, with a story seen previously in superior science-fiction films".