Based on contributions from leading scholars, this study generates a wealth of new empirical information about Latin American party systems. It also contributes richly to major theoretical and comparative debates about the effects of party systems on democratic politics, and about why some party systems are much more stable and predictable than others. Party Systems in Latin America builds on, challenges, and updates Mainwaring and Timothy Scully's seminal Building Democratic Institutions: Party Systems in Latin America (1995), which re-oriented the study of democratic party systems in the developing world. It is essential reading for scholars and students of comparative party systems, democracy, and Latin American politics. It shows that a stable and predictable party system facilitates important democratic processes and outcomes, but that building and maintaining such a party system has been the exception rather than the norm in contemporary Latin America.