Now that the liquidation of Europe's overseas empires is all but complete, the world is in travail, beset by problems of readjustment and groping for new relationships that may make possible the peaceful and prosperous coexistence of more than a hundred states of widely differing characters and needs. The age-old expansion of Europe in terms of military power, settlement, trade, proselytism, territorial rule and, finally, social dominance has come to an abrupt end. Thoughtful people, particularly in the Western world, are bound to reflect on this epochal upheaval, and to realize that one of the very great revolutions in human affairs has taken place. They must be impressed, not to say awed, by the thought that the political and social structure of our planet has undergone such fundamental alterations at the very time when science and technology are opening to view the vast possibilities as well as the dangers of the space age.
Historians and political scientists have for some time been grappling with the problems of expansion, without, however, having come to anything like generally accepted conclusions. Political controversy has seriously beclouded the meaning of the terms imperialism and colonialism, while scholarly analysis has revealed ever more clearly how loose and unmanageable these words and concepts really are. I take it that, in its broadest sense, imperialism means domination or control of one nation or people over another, recognizing that there may be many forms and degrees of control. But there is probably no hope of ever constructing a generalized theory of imperialism. Indeed, the most violent differences of opinion persist with regard to the causes and character even of modern European expansion, with little if any prospect of reconciling the Communist doctrine, so positively formulated by Lenin, with the manifold theories advanced by Western "bourgeois" writers.
However, among non-Communist critics and students substantial progress is being made in the evaluation of European imperialism. The initial phase of expansion, consequent to the great discoveries of the fifteenth and sixteenth centuries,