In Engines of Change, which is part the Oxford Studies in Postwar American Political Development series, Daniel DiSalvo provides the first full account of the role of these national intra-party "factions" in American politics. A faction, as defined here, is a party sub-unit that has enough ideological consistency, organizational capacity, and temporal durability to sustain intra-party conflict. Drawing from the last 150 years of American political history, DiSalvo explains how factions have shaped the parties' ideologies, impacted presidential nominations, structured patterns of presidential governance, and impacted the development of the American state. He demonstrates that factions can acquire the power to shape the parties' ideologies, impact presidential nominations, structure the patterns of presidential governance, and impact the development of the American state. Indeed, factions are often just as or more important than the parties themselves in driving political change. Sweeping in scope, Engines of Change promises to reshape our understanding of the forces most responsible for driving political change in modern American history.