Through strategy, a company seeks to sustain its competitive advantage. Yet only recently has the study of strategy begun to examine how long a specific advantage can be sustained. Based on a study of sustainability patterns in a number of industries, this article shows how the competitive pressures associated with product imitation can be predicted by identifying the core capabilities, or isolating mechanisms, that lie at the heart of a company's advantage. A number of these dynamic core capabilities are classified according to how fast they are duplicated. The imitation of capabilities shapes many strategic decisions in companies, indeed the distinctive character of companies, and that by thinking in these terms managers enhance their company's cohesiveness and responsiveness as they pursue their strategic mission in global markets.