Comparative politics involves both a comparative study of the political structures and functions of national political systems of various states and also a comparative study of the political institutions at work within a single state. The former is called horizontal comparative studies and the latter is called vertical comparative studies. Traditionally, under comparative governments emphasis was placed only upon horizontal comparative studies. Comparative politics is emerging as a distinct subdiscipline of political science, defined by both substantive and methodological criteria. Substantively, research in comparative politics seeks to account for variation among political units on consequential social, political, cultural and economic outcomes. Comparative politics research places these outcomes on dimensions, for example a dimension that goes from a Hobbesian state of nature to political order, and seeks to account for the placement of a political unit in a specific time period on that dimension. The book is useful for the researchers, teachers, and students of different levels.