HEN JACOB MARSCHAK died on July 27, 1977, he had just finished organizing the program of the annual meetings of the American Economic Association, a task that was his official duty as President-Elect of the Association. Marschak's election to the presidency of the AEA symbolized, in a sense, a reconfirmation by mainstream economists that Marschak was a bona fide member of the profession. It may seem to some that no such reconfirmation was needed. After all, Marschak's doctoral degree was in economics (Heidelberg, 1922), he had been a professor of economics in the United States since 1940, he was a charter member of the Econometric Society (and its President in 1946), and he was a member of the Cowles Commission for Research in Economics from 1943 to 1960 and its Director from 1943 to 1948. Nevertheless, on many occasions during the 1950s and 1960s I heard economists question whether Marschak had not actually left economics for other disciplines, such as psychology, information science, or some other part of that dimly perceived (and disapproved?) region sometimes called "behavioral science." During this period, Marschak's research and writing did, in fact, frequently take him beyond the boundaries of then-standard economics. It may also be true that he did his most creative and original work during this period. Fortunately, the boundaries of standard economics are somewhat flexible, and one [Author Note: I would like to thank K. J. Arrow and T. C. Koopmans for making available to me remarks on Marschak's like and work that will be published in the Amer. Econ. Rev., May 1978, and in Challenge, March/April 1978. I am also grateful to K. J. Arrow and L. H d c z for comments on the first draft of this note. In this note I have concentrated on three topics likely to be of intereat to readers of this journal, rather than attempt a balanced review of all of Marschak's work. A complete bibliography of Jacob Marschak's publications through 1971, excluding most book reviews and all newspaper articles, may be found in McGuire
and Radner (1972, pp. 335-341). Additional references may be found at the beginning of the first volume of the three-volume edition of selected papers by Marschak (1974).]