Professor C.E. Black of Princeton University called this "a valuable contribution to our understanding of the revolutionary movements that are now a worldwide phenomenon. It includes thoughtful essays on many varieties of revolution, considered in the light both of past developments and future prospects." The twentieth century was an age of revolution. Over many areas the two great ideologies of nationalism and communism spawned violent upheavals, often differing in form but aiming at the transformation of the existing order by means of coups d'etat, revolutions, and "wars of national...