The nature of selection. (Written circa 1971, published posthumously).

A model that unifies all types of selection (chemical, sociological, genetical, and every other kind of selection) may open the way to develop a general "Mathematical Theory of Selection" analogous to communication theory. [Note added by S. A. Frank: This previously unpublished manuscript was found among Dr. Price's papers when he died in 1975. In this paper Dr. Price did not provide a complete, general theory of selection. Rather, he argued why such a theory is needed and what some of its properties might be. The accompanying article provides commentary on this paper and describes Dr. Price's significant contributions to evolutionary genetics (S. A. Frank, 1995, J. theor. Biol. 175, 373-388).]