Far more than an intellectual puzzle for pundits, economists, and policymakers, economic growth—its makings and workings—is a subject that affects the well-being of billions of people around the globe. In , Elhanan Helpman discusses the vast research that has revolutionized understanding of this subject in recent years, and summarizes and explains its critical messages in clear, concise, and accessible terms. The tale of growth economics, as Helpman tells it, is organized around a number of themes: the importance of the accumulation of physical and human capital; the effect of technological factors on the rate of this accumulation; the process of knowledge creation and its influence on productivity; the interdependence of the growth rates of different countries; and, finally, the role of economic and political institutions in encouraging accumulation, innovation, and change. One of the leading researchers of economic growth, Helpman succinctly reviews, critiques, and integrates current research—on capital accumulation, education, productivity, trade, inequality, geography, and institutions—and clarifies its relevance for global economic inequities. In particular, he points to institutions—including property rights protection, legal systems, customs, and political systems—as the key to the mystery of economic growth. Solving this mystery could lead to policies capable of setting the poorest countries on the path toward sustained growth of per capita income and all that that implies—and Helpman's work is a welcome and necessary step in this direction.