Leon Walras (1834-1910) is one of the four or five most important economic theorists in the history of the science. The present book is a complete English translation of the second edition (1936) of his Etudes d'economie sociale (1896), in which he applies economic theory to real problems, presents the essence of his normative economic ideas, and reveals himself to have also been a great thinker on human nature, justice, mores, and the structure of scientific inquiry and knowledge. The book will be of interest to researchers and postgraduate students in the area of the history of economics as well as those interested in Walrasian topics, such as social justice, taxation, intellectual property, and land ownership.