A small number of firms create most of the jobs and economic growth in both rich and developing countries. The key to boosting economic dynamism may lie in supporting these high-growth firms. However, many policies that focus on firm size or sector may not be effective. Most firms struggle to maintain rapid growth, and the link between growth and productivity is often weak. To help firms grow better, we need policies that support innovation, skills, and global connections. The book suggests a new approach called the ABC framework: improving Allocative efficiency, promoting Business-to-business spillovers, and enhancing firm Capabilities.