Prehistoric stage of human society! What significant words! The capitalist economic order is the last phase of this stage, which is written in streams of blood and tears of the dispossessed and exploited, and to which is given the task of developing the productive forces and liberating men from the material fetters, so that they may enter into a life of mental culture. The materialist conception of history, unethical and unidealist like all natural science, opens up wide and elevating prospects. During thousands of years man struggled on the physical plane to obtain release from the animal kingdom, and was subjected to the discipline of unfeeling nature. After he had emerged from the animal kingdom, man laboured for thousands of years to lay the foundation of human society, a process which was performed under the hunger whip of stern taskmasters, and which powerfully stimulated the intellectual capacities of men, but only disclosed the ideal of justice and humanity as a remote and inaccessible star. The materialist conception of history has shown itself to be a fruitful method of historical investigation. Some aspects of this idea were uttered both before and during Marx's lifetime. The revolution in the positions of classes and the struggles which followed hard on the English industrial revolution (1760-1825), and everywhere attended the transition from an agrarian to an industrial State, were too palpable to be overlooked. It was Marx who fused these ideas, with the aid of the Hegelian dialectics made of them a method of investigation, and pressed them into the service of Socialism and historical research. II. CLASSES, CLASS STRUGGLES, AND CLASS-CONSCIOUSNESS. One of the most important contributions of Marx to the understanding of historical processes is his conception of social classes and of class struggles. Although, prior to Marx, there were historians and politicians who pointed out the part played by social classes in politics and in social convulsions, it was Marx who first grasped this conception in its entire scope and significance, giving it precise form, and making it an essential part of political and social thought. He refers to the subject in the Communist Manifesto in the following terms: "The Socialist and Communist systems properly so called, those of St. Simon, Fourier, Owen, and others, spring into existence in the early undeveloped period of the struggle between proletariat and bourgeoisie. The founders of these systems see, indeed, the class antagonisms, as well as the action of the decomposing elements in the prevailing form of society. But the proletariat, as yet in its infancy, offers to them the spectacle of a class without any historical initiative or any independent political movement."