In the Interest of Others develops a new theory of organizational leadership and governance to explain why some organizations expand their scope of action in ways that do not benefit their members directly. John Ahlquist and Margaret Levi document eighty years of such activism by the International Longshore and Warehouse Union in the United States and the Waterside Workers Federation in Australia. They systematically compare the ILWU and WWF to the Teamsters and the International Longshoremen's Association, two American transport industry labor unions that actively discouraged the pursuit of political causes unrelated to their own economic interests. Drawing on a wealth of original data, Ahlquist and Levi show how activist organizations can profoundly transform the views of members about their political efficacy and the collective actions they are willing to contemplate. They find that leaders who ask for support of projects without obvious material benefits must first demonstrate their ability to deliver the goods and services members expect. These leaders must also build governance institutions that coordinate expectations about their objectives and the behavior of members. In the Interest of Others reveals how activist labor unions expand the community of fate and provoke preferences that transcend the private interests of individual members. Ahlquist and Levi then extend this logic to other membership organizations, including religious groups, political parties, and the state itself.