The book is an analysis of the rise and fall of the Soviet empire in what, during the Cold War, was called 'Eastern Europe'. Based on new archival evidence, it focuses on the dynamics leading to the division of Germany - a process by default rather than design; the role played in that process by the Soviet Union under Stalin; the reasons why his successors, from Khrushchev to Chernenko, stubbornly clung to the division for almost half a century; their increasing realization of the 'costs of empire'; the failure of their attempts to limit East Germany 's dependence on West Germany; and the reasons why Gorbachev accepted the dissolution of the Soviet empire, abandoned his 'strategic ally' and consented to unified Germany's membership in Nato. The Soviet Union had overextended itself in the attempt to maintain imperial control by the application of 'hard power'. The lesson for today is obvious but Putin appears set to repeat the fateful course pursued by his Soviet predecessors.