The field of the comparative study of political party systems has been particularly fortunate to have been the focus of quite a number of substantial scholarly team efforts in recent years. Individual case studies are still appearing that follow Robert A. Dahl's model of the “patterns of opposition.” Terms such as “crisis of participation” or Sartori's “extreme pluralism,” from the book edited by Joseph La Palombara and Myron Weiner,2 are widely used in the description of party systems. Even the study of one-party systems and of national integration in developing areas is beginning to settle down to a common terminology that will increasingly allow comparison with the better-explored systems.