By embodying the hopes of a set of qualitative liberals who believed that postwar economic abundance opened up opportunities for self-development, David Riesman's bestselling The Lonely Crowd influenced the New Left. Yet Riesman's assessment of radical youth protest shifted over the course of the 1960s. As an antinuclear activist he worked closely with New Left leaders during the early 1960s. By the end of the decade, he became a sharp critic of radical protest. However, other leading members of Riesman's circle, such as Kenneth Keniston, author of the influential Young Radicals (1968), applied Riesman's ideas to create more sympathetic understandings of the New Left. Examining reactions to the New Left by Riesman and his associates allows historians to go beyond the common understanding of the key ideological divisions of the 1960s as existing between liberalism and radicalism or between liberalism and conservatism to better appreciate the significance of splits among liberals themselves.