The premise of this book is, simply, that politicians matter, that an understanding of the role played by politicians in the way that politics is carried out in their countries is, far from constituting a resurrection of outdated elitist theories, of vital importance in present-day Latin America. The authors consider politicians as both cause and effect. Drawing on pioneering field research on the opinions of Latin American legislators in 17 countries, they focus on two broad topics: political systems, as reflected in politicians' perspectives on the democracies and party organizations of which they are a part; and the role played by ideology, not only in shaping positions on issues, but also as a factor that gives coherence to parties. Their seminal work is central to the current political dynamics in the region, as well as to broader debates in political science.