This module presents a number of lessons from theoretical industrial economics for our understanding of corporate decision-making - such as price-setting, output-setting, investment in productive capacity, advertising and collusive behaviour. In this context, the role of industrial competition is emphasized and both the determinants of market structure and the imperatives for competition policy intervention are discussed. From these notes you should gain full knowledge and understanding of economic analysis that underlies the functioning of markets and industries and the behaviour of firms within. The discussion of competition policy and social welfare are also provided alongside notes on economic efficiency.