Book excerpt: These original contributions by some of today's leading macroeconomists and political economists explore a broad spectrum of social, political, and technological variables that encourage or impede economic growth. What political and economic factors stimulate growth and make an economy expand? These original contributions by some of today's leading macroeconomists and political economists explore a broad spectrum of social, political, and technological variables that encourage or impede economic growth. Topics range from economic reform and price flexibility to the economic effects of political coups and include both theoretical analysis and empirical results.During the past decade, economists have seen important new developments linking growth and business cycles to government policy. These contributions provide a clear understanding of these processes and their effect in shaping economic policy. They look at the welfare side of economics and offer strong economic models to explain the connection between social policies and economic growth. For example, John Londregan and Keith Poole address the economic effects of political coups, Torsten Persson and Guido Tabellini explore the question of whether inequality is harmful for growth, and Stephen Parente and Edward Prescott look at the role of technology adoption in stimulating growth.The essays cover a wide range of approaches. Several focus on the interaction between growth and the choice of policy, where policy reacts to economic and distributional considerations through a majority rule process. Others take the policy as given and focus on the empirical estimation of the speed of convergence of rates of growth across states and regions and the importance of externalities and knowledge spillovers for rates of growth. Essays about the business cycle fall into two broad categories. One, arising from the new political economy tradition, examines the effects of elections and price decontrols on the business cycle. The other explores the implications of optimal economic policies in a representative agent framework for the cyclical behavior of the economy.