Daniel Schlozman and Sam Rosenfeld argue that American political parties have become 'hollow'—dominating elections while failing at their core functions of building coalitions, developing policy, and mobilizing citizens. The book traces how parties evolved from nineteenth-century patronage machines through Progressive Era reforms to the contemporary situation where parties win power without knowing how to use it. The authors give particular attention to the Republican Party's transformation, arguing that its hollowing enabled capture by movement conservatives and ultimately by Donald Trump. Democrats face their own version of the problem: a party that commands diverse coalitions but struggles to deliver on their competing demands. Schlozman and Rosenfeld draw on historical scholarship and contemporary political science to diagnose dysfunction while resisting easy prescriptions. The book is essential reading for understanding why American politics feels simultaneously hyperpartisan and incapable of solving problems.