DAVID C. HAMMACK is Hiram C. Haydn Professor of History and Chair of the Committee on Educational Programs of the Mandel Center for Nonprofit Organizations at Case Western Reserve University. Previously he taught in the City University of New York and at Princeton University. Hammack has held a Guggenheim Fellowship and was a Resident Fellow at the Russell Sage Foundation. His research has also been supported by grants from the American Council of Learned Societies and the Aspen Institute Nonprofit Sector Research Fund. He is the author of Power and Society: Greater New York at the Turn of the Century and Social Science in the Making: Essays on the Russell Sage Foundation, 1907-1972, and editor with Dennis Young, of Nonprofit Organizations in Market Economy.