Given the centrality of political parties in modern democracies, most research on these systems either directly address their internal functioning and activities or question their critical role. Political science has moved from describing institutions to the thorough analysis of behavior within these institutions and the interactions between them. The inevitable consequences of the maturing and institutionalization of the discipline of political science in many countries include the forming of sub-fields and specialized research communities. At the same time the number of democracies has vastly increased since the 1980s and although not each attempt at democratization was eventually successful, more heterogeneous systems with some form of party competition exist than ever before. As a consequence, the literature addressing the large issues of party democracy spreads over many research fields and has become difficult to master for individual students of party democracy and party governance. The present volume sets out to review the behavior and larger role of political parties in modern democracies. In so doing the book takes its departure from the idea that the main contribution of political parties to the working of democracy is their role as vehicles of political competition in systems of government. Consequently the focus is not merely in the internal functioning of political parties, but rather their behavior the electoral, legislative, and governmental arenas. Thus several chapters address how political parties perform within the existing institutional frameworks. One more chapter looks at the role of political parties in building and adapting these institutions. Finally, two chapters explicitly address the party contributions to democracy in established and new democracies, respectively.