Jacob Marschak's work ranged over a great variety of topics in a long and productive intellectual career. Starting in the 1930s, his articles on measurement of economic variables and estimation of economic relationships provided foundation stones for the field now known as econometrics. Other early papers made seminal contributions to the theory of asset holding, with particular reference to demand for money and liquidity under conditions of incomplete information. This led to a third phase of his work, which combined axiomatic and experimental approaches to rational decision making under uncertainty. From this he moved to the topic of interindividual communication of information, and by a further extension, to the problem of optimal organization for collective decision. The work of this fourth phase was summarized in the classic monograph Economic Theory of Teams, coauthored with Professor Roy Radner of UC, Berkeley. A fifth phase was represented by interest in scientific method as a particular instance of decision making under uncertainty. And there was also a host of significant papers not fitting readily into the above classificatory system, among them works on statistical theory, labor mobility, inventory policy, and economics of atomic energy.