  Despite such frequent and widespread recognition of the logic, it was finally generalized analytically by Mancur Olson only in 1965 in his Logic of Collective Action. The odd mismatch of individual incentives and what may loosely be called collective interests is the independent discovery of two game theorists who invented the prisoner’s dilemma for two persons (see Hardin 1982a, 24–5) and of various philosophers and social theorists who have noted the logic of collective action in various contexts. In Olson’s account, what had been a fairly minor issue for economists became a central issue for political scientists and social theorists more generally. From early in the twentieth century, a common view of collective action in pluralist group politics was that policy on any issue must be, roughly, a vector sum of the forces of all of the groups interested in the issue (Bentley 1908). In this standard vision, one could simply count the number of those interested in an issue, weight them by their intensity and the direction they want policy to take, and sum the result geometrically to say what the policy must be. Olson’s analysis abruptly ended this long tradition; and group theory in politics took on, as the central task, trying to understand why some groups organize and others do not.