I have subtitled this paper "Economics of Product Characteristics to identify the set of recent developments that will be covered and to inform you that not all recent developments will be dealt with. This paper will not cover the recent work in systems of consumer demand equations: e.g., the linear e3q>enditure systems, additive-preference systems, Theil-Barten work, Houthakker and Taylor dynamic model. For discussions of these, see Barten (1977), Hassan, Johnson, and Green (1977), and Thell (1975, 1976). Another body of literature that I will not cover concerns probabilistic product-choice models, in which utility is a random function and the probability that a product is chosen depends upon the characteristics of the chosen product and of other products. Among the papers on this topic McFadden (1973, 1976) and Manski and Lerman (1977).