This paper surveys the results of mostly recent research on optimal aggregate economic growth models, and comments on the difficulties encountered and on desirable directions of further research.

This paper investigates Bohm-Bawerk's idea of a preference for advancing the timing of future satisfactions from a somewhat different point of view. It is shown that simple postulates about the utility function of a consumption program for an infinite future logically imply impatience at least for certain broad classes of programs. The postulates assert continuity, sensitivity, stationarity of the utility function, the absence of intertemporal complementarity, and the existence of a best and a worst program. The more technical parts of the proof are set off in starred sections.

A study of the efficient allocation problem in production by the evaluation of the merits of private or corporate enterprise versus a centrally directed economy. Presented before a joint meeting of the American Statistical Association, the American Economic Association, and the Econometric Society in New York City, December 29, 1949.