Between 1996 and 2006, the William and Flora Hewlett Foundation invested over $20 million in the Neighborhood Improvement Initiative (NII), an ambitious effort to help three neighborhoods in the Bay Area reduce poverty and develop new leaders, better services, more capable organizations, and stronger connections to resources. In the end, despite some important accomplishments, NII did not fulfill its participants’ hopes and expectations for broad, deep, and sustainable community change. In those accomplishments and shortcomings, and in the strategies that produced them, however, lies a story that is mirrored in many other foundations’ community change initiatives. This report examines NII’s experience in the context of other foundation-sponsored initiatives: its ideas, its use of community foundations as intermediaries, and its approach to supporting and evaluating change. The report offers observations about improving the quality of the philanthropic enterprise—the strength of the ideas or theories, the degree to which the theories are implemented consistently and effectively over time, and the collective learning that is generated for the field. The authors are indebted to the Hewlett Foundation for commissioning this retrospective analysis in a field where few foundations have been willing to contribute to this level of critical self-analysis and candid public debate. We believe that philanthropy has an important role to play in strengthening poor communities and improving outcomes for the people who live in them and we hope that this report will stimulate further reflection and action toward this end.