traces the origins, extension, marginalization and revival of evolutionary approaches to social theory from the Enlightenment through the beginning of the 21st century. It demonstrates how changes in understandings of social evolution corresponded to changes in definitions of Political Economy and how both reflected changes in the Philosophy of Science. This book is written for students and researchers alike in all the social sciences. Economists will benefit from understanding how ideas about evolution in Economics corresponded to ideas about evolution in other social sciences, and Social Scientists outside of Economics will benefit from understanding how Economics has related to their discipline.