IN 1975 THE NOBEL PRIZE for economics was awarded to Tjalling C. Koopmans and Leonid V. Kantorovich for their contributions to the theory of the optimal allocation of resources. Koopmans' work in activity analysis, linear programming, and optimal growth, together with his influential doctrine of the price implications of optimality, is central to neoclassical economics. By contrast, Kantorovich's work in these areas remains poorly understood in the West. Many economists would have a hard time describing his contribution, much less justifying the award of a Nobel Prize to it. This paper aims at redressing this regrettable situation. Earlier assessments of Kantorovich's work have been made by Leif Johannsen (1976) and Aron Katsenelinboigen (1978-79). The brief entry in the New Palgrave by Kantorovich's coauthor V. Makarov (1987) as well as Kantorovich's Nobel autobiography and acceptance speech (Kantorovich 1976a, 1976b) should also be mentioned. However, the appearance of new material, most notably Kantorovich's own glasnost-era memoir (1987), as well as work on the nature and computation of his resolving multipliers by Roy Gardner (1988), justifies a new assessment. The argument proceeds by stages: (1) Kantorovich's life, in many ways remarkably similar to that of John von Neumann, (2) the discovery of optimal planning, the basis of the work for which he won Nobel Prize, (3) the computation of an optimal plan, in which his resolving multipliers play a crucial role, and (4) his indirect influence on the current restructuring of the Soviet economy, perestroika. In this way, the reader should come to a clearer understanding of the man and his economics.