This book is a practical guide to developing a scaleable, social entrepreneurship venture (SEV). The author uses the popular "business model" concept and shows the important modifications that are required to build large, sustainable organizations to address social problems in the developing world. The author spent three years as the CFO of One Laptop per Child, one of the largest SEVs, and worked for over twenty years in the developing markets of Latin America and Asia. In a ten year period in Indonesia, where per capital income was only $600, he built a publicly traded billion-dollar retail company. Much of the thinking in the book has been shared with students at Florida International University and MIT Sloan where the author teaches.