This leading text provides a concise and broad-ranging introduction to the contemporary study of political theory. Each chapter discusses a cluster of interrelated concepts and examines how they have been used by different thinkers and traditions and explores related debates and controversies. The fourth edition of this highly successful and accessible book has been substantially revised and updated and includes extra attention throughout to non-Western approaches and international political theory. Systematically covering the foundational concepts that have focused debate from Aristotle, Rousseau, Marx and Mill to the present day, this is essential reading for undergraduate and postgraduate courses on political thought and political philosophy. With increased discussion of the global dimensions of political thought it will appeal to an international audience, as well as to those lecturers interested in broadening their students' horizons.