A revelatory look at modern liberalism's historical evolution and enduring impact on contemporary politics and society.    Since the 1960s, American liberalism and the Democratic Party have been remade along professional class lines, widening liberalism's impact but narrowing its social and political vision. In Mastery and Drift, historians Brent Cebul and Lily Geismer have assembled a group of scholars to address the formation of "professional class liberalism," and its central role in remaking electoral politics and the practice of governance. Across subjects as varied as philanthropy, consulting, health care, welfare, race, immigration, economics, and foreign conflicts, the authors examine not only the gaps between liberals' egalitarian aspirations and their approaches to policymaking but also how the intricacies of contemporary governance have tended to bolster professional class liberals' power. The contributors to Mastery and Drift all came of age amid the development of professional-class liberalism, giving them distinctive and important perspectives in understanding its internal limitations and its relationship to neoliberalism and the Right. With never-ending disputes over the meaning of liberalism, the content of its governance, and its relationship to a resurgent Left, now is the time to consider modern liberalism's place in contemporary American life.