This book is an introduction to the philosophical ideas of Plato, Rene Descartes, Baruch Spinoza, and Immanuel Kant on the role of reason which have contributed to the evolution of sociological thought. Reason, according to Rickman, has a relevance to sociology that has not been explored. Because he is interested in the philosophical reflections which proved influential for understanding the social world, he deals systematically with the four philosophers' central arguments and one or more of their most important and easily available texts. The book's bibliography lists books quoted and referred to in the text and offers suggestions for further reading in the philosophy of the social sciences.