This study deals with recent changes in the industrial organization of grocery retailing. We make no pretense at taking the full measure of all changes which are relevant to the performance of the dynamic industry. Rather, we have concentrated our efforts on two major tasks. First, we have attempted to measure certain market characteristics which economic theory and emprical studies suggest as being important determinants of competitive behavior. This involved the often tedious task of compiling data necessary to understand the nature and to measure the magnitude of these changes. Second, we attempted to interpret the probable implications of these changes for the market performance of grocery retailing and related industries.