The authors examine the histories of four business-to-business relationships in the United States: advertising agencies and clients, textile agents and mills, the Pullman Car Company and railroads, and independent department stores and their resident buying offices. The authors’ goals are to gain perspective on how marketing relationships evolve over time and identify those factors that foster closer relationships and those that attenuate relationships. The results show that economic growth, information asymmetry partially prompted by geographic dispersion, entry barriers in one or both industries, dependence asymmetry, and economies of scale are important environmental forces that impinge on relationship development in all four cases.