This article was part of a special supplement in the Food and Nutrition Bulletin on the Alive & Thrive (A&T) project. The Supplement presented field-tested design and implementation frameworks for rapid scale-up of programs to prevent stunting during the “window of opportunity.” It documented how infant and young child feeding (IYCF) programs were designed and successfully scaled up in Bangladesh, Ethiopia, and Viet Nam from 2009 to 2013. An understanding of how to strengthen delivery systems to programmatically achieve scale in distinct country contexts and how to motivate behavior change in different populations, from decision makers to mothers, is critical for realizing the full public health impact of nutrition interventions.