How did the 1950s become "The Sixties"? This is the question at the heart of Daniel Horowitz's On the Cusp. Part personal memoir, part collective biography, and part cultural history, the book illuminates the dynamics of social and political change through the experiences of a small, and admittedly privileged, generational cohort. A Jewish "townie" from New Haven when he entered Yale College in fall 1956, Horowitz reconstructs...