Lectures given at a Summer School of the Centro Internazionale Matematico Estivo (C.I.M.E.) held in L'Aquila in Italy on August 29-September 7, 1965. The book contains:G.Th. Guilbaud Les equilibres dans les modeles economiques, H.W. Kuhn Locational problems and mathematical programming, M. Morishima The multi-sectoral theory of economic growth, B. Martos, J. Kornai Experiments in Hungary with industry-wide and economy wide programming, A. Prekopa Probability distribution problems concerning stochastic programming problems, R. Frisch General principles and mathematical techniques of macroeconomic programming.