Taking successful development interventions to scale is critical if the world is to achieve the Millennium Development Goals and make essential gains in the fight for improved agricultural productivity, rural incomes, and nutrition. How to support scaling up in these three areas, however, is a major challenge. This collection of policy briefs is designed to contribute to a better understanding of the experience to date and the lessons for the future.The authors of the 20 policy briefs included here explore the experience of scaling up successful interventions in agriculture, rural development, and nutrition under five broad headings: the role of rural community engagement, the importance of value chains, the intricacies of scaling up nutrition interventions, the lessons learned from institutional approaches, and the experience of international aid donors.