On December 1, 1934, a disaffected, psychotic party worker stalked Sergei Kirov, the first secretary of the Leningrad Communist Party, as he walked the hall to his third-floor office and shot him in the back of the head. From this act flowed an ever-widening cascade of murderous events. Stalin charged Grigory Zinoviev and Lev Kamenev, once leaders of the opposition against him, with "moral complicity" in Kirov's killing. He then spread the blame to much of the Leningrad party organization and eventually, as the Communist Party's purge swelled, to all manner of supposed opposition figures, including so-called Trotskyite terrorists. In mainstream Western historical scholarship, Kirov's murder has long been thought to have been plotted by Stalin. In a post-Soviet Russia fascinated with more titillating theories, some have alleged that the assassin's motive was that of a jealous husband. Lenoe's massive volume combines biography -- of both Kirov and his killer, Leonid Nikolaev -- with an assessment of the vast documentation yielded by the Soviet archives, and it concludes that Nikolaev most likely acted on his own. As the documents and witnesses tell their story, the monstrous use that Stalin made of the event stands still more baldly exposed.