Milanovic is a leading contemporary scholar on inequality, particularly known for estimates of trends in inequality and the role of globalization in decreasing inequality between countries, even if inequality has increased in some countries. This book examines the evolution of theories of inequality and its fundamental causes. It is organized around chapters on five key thinkers, starting in chronological order with Quesnay (before the French revolution), Smith, Ricardo, Marx, Pareto, and ending with Kuznets (during the Cold War). These chapters on each individual provide useful and clear representations of core theories, using equations and contemporary concepts and insights. But to me the most interesting part of the book is the larger comparative perspective and the final chapter on the evolution of studies of inequality. The earlier writers had limited access to data and primarily looked to theoretical models for insights on causes. As empirical data have become increasingly available, the original guesstimates often seem remarkably prescient. More data can clearly be useful, but empirical work devoid of clear theoretical underpinnings have often come up short.  Early models tended to emphasize class as the origin of inequality and hence its defining characteristics as potential causes of change. Marx, for example, was primarily focused on the end of the class system and had little interest in changes in inequality within a capitalist system. Income distributions is in many ways a recent concern, although the recent work by Piketty and others underscore the core role of non-wage income in inequality. As such, this is more than a retrospective, and essential reading for anyone interested in inequality and change.