In this chapter we examine regulation and antitrust, or the role of government in the economy. the government’ s traditional role of maintaining law and order and providing for national defense has greatly expanded over time, particularly during the past few decades, so that today it affects most industries, firms, and consumers. It is important therefore, thaT managers be sufficiently familiar with business and regulations to know when to seek legal help in the conduct of their business and to be able to recognize when competitors are harming the firm through illegal business practices.