The Cold War of the 20th century seems clear cut, in retrospect: a galvanizing competition to rally free and market-oriented societies against a godless communist empire. But the 21st century has brought about new, more complicated conflicts. Historian Stephen Kotkin examines U.S. relations with China, Russia, and Iran from the 1970s to the present. Professor Kotkin won the seventeenth annual Council on Foreign Relations Arthur Ross Book Award for Stalin: Waiting for Hitler, 1929–1941 (Random House), the second volume of a definitive biography of Joseph Stalin. The first volume, Paradoxes of Power, was nominated for a Pulitzer.