In 1917, Bolshevik revolutionaries came to power in the war-torn Russian Empire in a way that defied all predictions, including their own. Scarcely a lifespan later, in 1991, the Soviet Union collapsed as accidentally as it arose. The decades between witnessed drama on an epic scale--the chaos and hope of revolution, famines and purges, hard-won victory in history's most destructive war, and worldwide geopolitical conflict, all entwined around...