Revolutions are melancholy moments in history--brief gasps of hope that emerges from misery and disillusionment. This is true for great revolutions, like 1789 in France or 1917 in Russia, but applies to lesser political upheavals as well. Conflict builds into a state of tense confrontation, like a powder keg. When a spark is thrown, an explosion takes place and the old edifice begins to crumble. People are caught up in an initial mood of elation, but it does not last. Normality catches up.

Why do revolutions occur? In this completely revised edition of The Modern Social...