In his famous essay on “The Tragedy of the Commons,” Hardin (1968) derived predictions of environmental disaster from the proposition that people are entirely selfish by nature. The article has had two important effects. In regard to public policy, it has lent intellectual support to approaches based on Hardin's idea that natural resources can be sustained only if management responsibilities lie in a single place. Policymakers in many countries took this advice in one of two directions—giving responsibility to government agencies to act on behalf of all, or devolving responsibility to individual resource users in campaigns of privatization intended to empower markets.