What really happened to Yuri Gagarin, the first man in space, who died mysteriously in a plane crash? Why weren't the Russians the first to put a man on the moon? Accomplished space historian Cassutt (Who's Who in Space) offers an intriguing account of Russia's space program as a gripping, atmospheric Cold War saga. In 1965, Russian engineering student Yuri Ribko--son of combat pilot hero Col.-Gen. Nikolai Ribko--visits his mentor, Vasily Filin, in the hospital. Filin works at the Experimental Design Bureau Number 1, the organization that launched Sputnik. Coincidentally, Sergei Korolev, a genius missile designer and head of the bureau, dies under highly questionable circumstances in the same hospital. Yuri's Uncle Vladimir, an official in State Security, recruits Yuri to spy on Filin's organization for the KGB and discover who killed Korolev. Yuri finds himself torn between loyalty to his mentor and to his father, and the excitement of working for his uncle. Life is further complicated when Yuri's love, Marina, has an affair with his roommate, Lev, who is working for an opposing faction in the politically sensitive rocket program. The fiery end of Soyuz 1 and the death of space hero Gagarin, who was also in the hospital the day Korolev died, are followed by a series of ignominious Russian fiascoes, both on the ground and in space. As the foulups continue, suspicions escalate that someone is sabotaging the program. Yuri is aware he is being manipulated, but he is uncertain by whom or why. Tingling with political tension and ringing with authenticity, this dark, edge-of-your-seat thriller gives a launch-by-launch account of Russia's abortive struggle to keep abreast of NASA and win the space race. (Feb. 13) Forecasts: It's debatable whether more than a few care about the cosmonauts of yesteryear, but some interesting marketing plans, including ads in Scientific American, will help this novel; and a film or TV translation is a possibility, particularly given Cassutt's experience as a writer/producer for Max Headroom and Beverly Hills 90210.