David Horowitz spent the first part of his life in the world of the Communist-progressive left, a politics he inherited from his mother and father, and later in the New Left as one of its founders. When the wreckage he and his comrades had created became clear to him in the mid-1970s, he left. Three decades of second thoughts then made him this movement's principal intellectual antagonist. "For better or worse," as Horowitz writes in the preface, "I have been condemned to spend the rest of my days attempting to understand how the left pursues the agendas from which I have separated myself,...