For students of social democracy, the big debate of the contemporary era concerns change: Has the Left been transformed in fundamental ways over the past decades, and if so, how and why? Gerassimos Moschonas's new book attempts to give a definitive answer to at least the first of these questions by marshaling an impressive amount of evidence in a wide range of areas relevant to the development of social democracy. As the book title indicates, he falls firmly into the camp of those who believe that the Left has indeed undergone a “great transformation.” As he puts it: “[A]ccording to the central hypothesis of this book … we are witnessing a recasting of the European social democracies … [it is] the end of a political and social cycle” (p. 6). But Moschonas understands that such a claim alone is both commonplace and unhelpful; a real contribution to the debate requires clearly delineating what social democracy was and what it has become, and as anyone who knows the literature on social democracy can attest, this is easier said than done.