Leon Walras was an economics professor at the University of Lausanne in Switzerland until his retirement in 1902. Jevons, Menger, and Walras are considered the founders of the "marginal revolution", due to their simultaneous development of marginal u tility. In the 1870's, Jevons in England, Menger in Austria, and Walras in France, focused on the preferences of consumers and the demand for commodities, transforming economic theory from classical to neo-classical.

Walras is also credited with the discovery of general equilibrium theory, which has become known as "Walrasian general equilibrium". In 1874 Walras stated that under conditions of constant or diminishing returns to scale, an economy composed of consumer s and producers with maximizing behavior will attain a general equilibrium. General equilibrium theory is unique in that it uses microeconomic tools to answer macroeconomic questions. In attempting to show a whole economy in equilibrium, Walras built a s ystem of simultaneous equations, then showed that due to the fact that the number of equations equaled the number of unknowns, "the system could be solved to give the equilibrium prices and quantities of commodities. He developed the tâtonnemen t process to show the process toward general equilibrium. The tâtonnement proces for finding an equilibrium involves having an auctioneer try out various prices, request information on demand and supply, and search for a set of prices so that demand equals supply in all markets. Walras's assumption throughout was that no actual exchange was carried out until equilibrium was reached. he also developed Walras' Law, which states that if all but one market is in equilibrium, the last m arket must also be in equilibrium.

Works by Leon Walras:

• Elements of Pure Economics