Ever since Aristotle, the comparative study of political regimes and their performance has relied on classifications and typologies. The study of democracy today has been influenced heavily by Arend Lijphart’s typology of consensus versus majoritarian democracy. Scholars have applied it to more than 100 countries and sought to demonstrate its impact on no less than 70 dependent variables. This paper summarizes our knowledge about the origins, functioning, and consequences of two basic types of democracy: those that concentrate power and those that share and divide power. In doing so, it will review the experience of established democracies and question the applicability of received wisdom to new democracies.