Michael Harrington, the democratic socialist whose 1962 book The Other America helped inspire the War on Poverty, wrote this treatise in the final years of his life as both summation and prospectus. Harrington engages with socialism's history from Marx through the twentieth century's successes and failures, arguing that understanding what went wrong is essential to imagining what might go right. He develops the concept of 'visionary gradualism': the insight that fundamental transformation requires both radical goals and practical steps, that revolutionaries must also be reformers. The book examines social democracy's achievements in Western Europe while acknowledging its limitations, analyzes Soviet-style communism's betrayal of socialist ideals, and considers socialism's prospects in the developing world. Harrington argues that socialism remains necessary because capitalism cannot solve the problems of inequality, environmental destruction, and alienation that it generates, but he insists that socialism must be democratic to its core or it becomes merely another form of domination. Writing as the Cold War ended, he sensed that socialism's moment might be arriving even as its reputation seemed at its nadir. This book offers both historical perspective and moral argument for readers seeking to understand why socialist ideas persist and what they might offer a world still struggling with capitalism's failures.