Raymond Aron made major investigations into the dialectic between war and peace, and also developed a sophisticated theory of international relations. Despite this, his body of work has been overlooked compared to that of his more famous contemporaries. This book shines a light on both the man and his work on ideological critique, the philosophy of history, international relations and political economy. The book also discusses Aron's political legacy and argues that a number of his critiques and theories can help us address many of the problems and conflicts of the 21st century.