On the morning of April 26, 1986, a Soviet nuclear plant at Chernobyl (near Kiev) exploded, pouring radioactivity into the environment and setting off the worst disaster in the history of nuclear energy. Now a former Soviet scientist gives a comprehensive account of the catastrophe.A major contribution to the literature. . . . Medvedev sees Chernobyl as a watershed in the use of nuclear energy and the policies that control it. A damning history of the Chernobyl affair, from its origins in the plant's primitive design and careless management to the economic and political crisis the accident precipitated. Clenn Garelik,