Arend Lijphart is Professor Emeritus of Political Science at the University of California, San Diego. He is a member of the American Academy of Arts and Sciences and a past president of the American Political Science Association. In this interview, we discuss his book Patterns of Democracy: Government Forms and Performance in Thirty-Six Countries (Yale University Press, 2012), now in a newly updated edition. The book is an empirical study of power-concentration and power-sharing in 36 democracies around the world during the period 1945 to 2010. Professor Lijphart finds strong correlations between institutional arrangements, such as a country's electoral system, and quantifiable aspects of democratic quality, including political and economic equality, governmental accountability, rates of incarceration, and gender equality. Patterns of Democracy has been called "controversial," "magnificent," and "the best-researched book on democracies in the world today."