This work is written at an intermediate level and is designed for undergraduate microeconomics courses. Postgraduate courses in which microeconomic theory is taught at not too specialized a level can also make use of the text. The book is presented in three parts. Part 1 examines the behaviour of the consumer and other buyers, and develops the basic tools of analysis of the behaviour of the firm, its revenue and cost curves. Part 2 deals with the theory of the firm, concentrating on oligopoly, the main form of market structure in the modern industrial world. Part 3 discusses the theory of factor pricing, general equilibrium theory and welfare theory. It thus covers all the topics usually included in textbooks on price theory in addition to offering a comprehensive treatment of classical and modern theories of the firm.