This book argues that what the 21st century now faces is an ideological assault based on hatred of Jews which is as serious as any major threat to universal values as the world has faced. Anti-semitism is the visible language and action of a deeper threat to world peace, to the achievements of the human spirit we call the Enlightenment, and undermines vital work to address problems like poverty and the challenges of the environment. Denis MacShane's survey of 21st century anti-semitism is based on the All-Party Commission of Enquiry which was chaired by the author in the UK. His book considers examples in Europe and how anti-semitism is now a linking mechanism between different extremisms, usually but not exclusively of the Right. It lists in detail the anti-semitism in national party politics, including the European Parliament, and it examines how Holocaust denial is not a question of liberal free-expression issues but an organised ideological position. The new anti-semitism arises from three main sources: state-sanctioned anti-semitism; that of terrorist movements like Al Qaeda; and that of political movements like the Muslim Brotherhood and its off-shoots and spokesmen. The book is both a cri de coeur for a new tolerance and a resolution to throw light on 21st century anti-semitism, which has left Europe to become a new form of mobilising politics across many continents.