This module begins by looking at some advanced topics in monopoly behaviour, before investigating how firms interact in markets. The latter is the core material of industrial organisation theory, and we develop the game theoretic approaches to oligopoly pricing, product differentiation, and strategic investment. Applying these core ideas, we investigate topics such as strategic entry deterrence mergers, 2-sided markets, R&D, patents and vertical relationships including exclusive dealing, other restraints and rebates. Although this is essentially a module in applied microeconomic theory, emphasis is placed on empirical relevance, testability and policy analysis.