Mancur Lloyd Olson, Jr. (pronounced /ˈmænsər/[1] or /ˈmæŋkər/; January 22, 1932 – February 19, 1998) was a leading American economist and social scientist who, at the time of his death, worked at the University of Maryland, College Park. Among other areas, he made contributions to institutional economics on the role of private property, taxation, public goods, collective action and contract rights in economic development. Olson focused on the logical basis of interest group membership and participation. The reigning political theories of his day granted groups an almost primordial status. Some appealed to a natural human instinct for herding, others ascribed the formation of groups that are rooted in kinship to the process of modernization. Olson offered a radically different account of the logical basis of organized collective action.

This book develops an original theory of group and organizational behavior that cuts across disciplinary lines and illustrates the theory with empirical and historical studies of particular organizations. Applying economic analysis to the subjects of the political scientist, sociologist, and economist, Mr. Olson examines the extent to which the individuals that share a common interest find it in their individual interest to bear the costs of the organizational effort.

The theory shows that most organizations produce what the economist calls "public goods"--goods or services that are available to every member, whether or not he has borne any of the costs of providing them. Economists have long understood that defense, law and order were public goods that could not be marketed to individuals, and that taxation was necessary. They have not, however, taken account of the fact that private as well as governmental organizations produce public goods.