<p>The article constructs and validates a new economic inequality index and calculates such indexes for modern capitalist societies and varieties of capitalism. It first overviews the state of the extant literature on economic and social inequality and its composite indexes and estimations or specific measures. It then advances and elaborates theoretical and empirical considerations about constructing a composite and comprehensive index of economic inequality and of broader economic-social inequality. It also collects and describes data and their sources and the method of empirical analysis. It presents the results of the analysis, including those of statistical analyses and of an exploratory analysis of inequality indexes among OECD countries and varieties of capitalism. Lastly, it analyzes the results, considers their theoretical and empirical relevance and outlines directions for further research.</p>