Dr. Kris Kelvin is the protagonist and narrator of Solaris. He is a psychologist who has spent the last 12 years researching the titular planet’s ocean through texts. The novel begins with him completing a 16-month flight to the space station hovering above the planet. Kris expects to work alongside his mentor, Dr. Gibarian. He defines himself as a “Solarist,” a person dedicated to understanding Solaris’s ocean as a life-form in the hopes of communicating with it.

Ten years ago, Kris’s 19-year-old wife Rheya died by suicide, injecting herself with a drug after an argument. He believes himself responsible for her death, and the morning after his first night on the station, he encounters a perfect replica of her, a visitor sent to him by Solaris’s ocean. Overall, he is an emotional person who grows angry with his fellow scientists, Dr. Snow and Dr. Sartorius. Kris’s feelings toward “Rheya” begin as fear and develop into deep affection, to the point that he trusts her more than his human colleagues. The novel ends with him bidding the ocean farewell, still longing for the deceased Rheya—the original and the replica.