To approach the management of populations by way of “population quality” is to attempt to see the world from the organism's point of view. From that vantage point, “populations” no longer appear to be inert masses passively responding to changing environmental pressures. Instead, they become heterogeneous mixtures of individuals differing markedly in their ability to survive particular stresses. Consequently, whether they are to be managed protectively, to sustain yields, or destructively, to dispose of pests, such populations will respond most consistently and predictably to management policies that exploit the effects which some of their members have on the numbers and structure of subsequent generations. Pest management, for example, would be better served by methods that would selectively discriminate against reproductively superior members of a generation than by methods that merely increase mortality indiscriminately, with no thought for the qualities of the survivors. Examples from laboratory, field, and simulation studies of the western tent caterpillar,Malacosoma californicum pluviale(Dyar), illustrate these points.