This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book begins with an account of Charles Darwin's own life and work, followed by a summary of his theory as it was first publicly presented in The Origin of Species. It also begins with an examination of the deductive core of Darwinism, and a general discussion of its actual and alleged philosophical presuppositions and philosophical implications. The book deals with three major and more particular Movements and Ideas topics: the relations and lack of relations between the work of Darwin and that of such social science predecessors as Malthus and the Scottish founding fathers; the Marxist contention that Karl Marx did for sociology what Darwin did for biology; and the present claims and possible scope of the projected future science of sociobiology. Finally, it examines the suggestions that Darwin's theory provides a guarantee of progress and a foundation for an evolutionary ethics.