The Planet Savers

The Planet Savers is a science fiction book by Marion Zimmer Bradley. It is part of her Darkover series. To uncover a cure for the periodic 48-year-fever, known as Trailmen's fever, Dr. Randall Forth convinces a coworker, Dr. Jay Allison, to undergo hypnosis. He calls forth a secondary personality, Jason Allison, who is outgoing and an experienced mountaineer, while Dr. Jay Allison is a cold, scientific man with no outdoor proclivities... This is just the beginning of a fantastic internal adventure!