Many political regimes today draw such legitimacy as they have from a revolution: the destruction of an existing political elite and its replacement by a different group or groups drawn from inside the same society. A large part of the ideological dispute in world politics has come in consequence to turn on an interpretation of the character of revolutions as political and social events. It is extremely difficult to separate ideological assessments of the desirability or otherwise of what has occured in revolutions from causal explanations of why these revolutions occurred, and both major traditions in the analysis of revolutionary phenomena have been damaged by their failure to distinguish clearly between explanation and assessment. In examining eight major revolutions of the twentieth century, John Dunn helps readers to remedy this state of affairs by thinking for themselves.