After decades of neglect, volatile food prices and the persistence of hunger and malnutrition have brought agriculture and nutrition to the forefront of the international development agenda. As governments, donors, and other key actors deepen their commitments, they are also increasing their focus on how successful development interventions can be “scaled up,” meaning how they can be expanded, replicated, and adapted to new and different contexts, for greater and sustained impact. In late 2011, IFPRI’s 2020 Vision Initiative approached Johannes Linn to develop a set of policy briefs that would contribute to a better understanding of scaling up in agriculture, rural development, and nutrition. The authors and other experts met at a workshop in Washington, DC, in January 2012, to discuss their draft briefs. The resulting series brings together a variety of experiences from around the world, delineates different pathways for scaling up, identifies both the key drivers that push the scaling-up process forward and the key spaces that enable initiatives to be scaled up, and outlines the lessons learned. These briefs were written by a wide range of actors, from local communities and nongovernmental organizations to private businesses and donors. They provide an invaluable perspective on the challenges and opportunities for successful scaling up.