Some might consider the task of producing an encyclopedia for an emerging field of study a foolish, if not futile, undertaking. From time to time over the course of preparing this work, I did indeed feel this to be true. Time has won out, and this work represents a first of its kind in attempting to provide an overview of philanthropy as well as of the nonprofit, voluntary, independent, or third sector (terms all used interchangeably) in the United States. Philanthropic and nonprofit studies have enjoyed a major growth spurt over the past twenty-five years in the United States, with recent increased attention around the globe. However, some still see the field as a marginal academic enterprise.With substantial contributions by many scholars in various disciplines and professional fields, philanthropic and nonprofit studies programs have given students and teachers alike a fresh perspective on critical issues in our society.