Donald A. Walker received a Ph.D. in Economics from Harvard University, Massachusetts. He specializes in microeconomic theory and the history of neoclassical economic thought. Dr Walker was the president of the History of Economics Society (1987–8), named Distinguished Fellow of that Society (2006), editor of the Journal of the History of Economic Thought (1990–8), and founder and first president of the International Walras Association (1997–2000). Among numerous other publications, he is the author of two books and many articles on the writings of Léon Walras, including Walrasian Economics (Cambridge, 2006). Jan van Daal received a Ph.D. from Erasmus Universiteit Rotterdam. He has researched and taught in the areas of mathematical economics and published on demand systems, aggregation problems, and the theory and history of general economic equilibrium. Dr van Daal specializes in research on the life and works of Léon Walras and has published, among other writings, The Equilibrium Economics of Léon Walras (with Albert Jolink, 1993), the translation of Walras' Études d'économie appliquée (2005), and the translation of Walras' Études d'économie sociale (with Donald A. Walker, 2010).