Over the past three decades, the study of nonprofit and voluntary organization has boomed. Research centers have been created at several dozen universities around the country and a growing body of research has been produced by scholars from the full range of social science disciplines. One of the most pronounced challenges in writing about the nonprofit sector has long been the difficulty in actually defining the boundaries of the subject matter under study. Two major trends have exacerbated these definitional issues: The widespread reliance on fee-based services charged to customers has made some of the larger nonprofits look ever more like businesses. At the same time, a growing dependence by nonprofits, particularly in the human services, on government funding has erased to some extend the lines separating the nonprofit and public sectors. Taken to an extreme, this blurring of lines actually suggests that the nonprofit sector may be neither