Part I. What is competition? And monopoly?. -- Competition. -- Price and nonprice competition. -- The measurement of concentration. -- A theory of oligopoly. Part II. The determinants of concentration. -- Barriers to entry, economies of scale, and firm size. -- The economies of scale. -- Monopoly and oligopoly by merger. -- The dominant firm and the inverted umbrella. -- Imperfections in the capital market. -- A note of patents. Part III. Topics in market behavior. -- The division of labor is limited by the extent of the market. -- A note on profitability, competition, and concentration. -- A theory of delivered price systems. -- A note on block booking. -- The economics of information. -- Information in the labor market. -- The kinky oligopoly demand curve and rigid prices. -- Administered prices and oligopolistic inflation. Part IV. Antitrust policy. -- Restraints on trade in the common law. -- The economic effects of the antitrust laws. -- Mergers and preventive antitrust policy.