Whether as a solution to problems of political legitimacy or social mistrust, as a way of involving civil society, or as a method of crafting more effective “third way” policies, collaborative governance has been a topic of renewed interest for political scientists and policy intellectuals. Carmen Sirianni's Investing in Democracy: Engaging Citizens in Collaborative Governance (Brookings, 2009) is an important new book that raises many of these issues. Perspectives on Politics is a forum for raising questions of interest to a broad range of political scientists. In this symposium, we have asked a number of prominent political scientists and policy analysts to assess the book and to address two broader questions: in what ways does the book draw from and add to political science scholarship, and in what ways does political science scholarship help to shed light on the book's core themes?