There was once a general consensus on the Left that anti-Semitism, derided as 'the socialism of fools', had no place in the Labour movement. No longer. Having led his party to its worst defeat since 1935, Jeremy Corbyn's humiliation was compounded when in October 2020, Labour was found by the Equality and Human Rights Commission to have been in breach of the Equality Act of 2010 on three separate counts of unlawful anti-Semitic acts while he was Party Leader. Corbyn himself was criticised by the Commission for protecting those committing such acts, and had the party whip withdrawn for rejecting its findings. In 2022, Corbyn publicly opposed NATO providing Ukraine with the military means to resist Putin's invasion, and after its massacre of more than 1,000 Jewish civilians on October 7, 2003, refused to condemn Hamas as a terrorist organisation. This book places the Corbyn affair in the context of a general crisis of the global Left, one that has been fuelled by a toxic mix of an obsessive anti-Zionism, Islamophilia, political correctness, a loathing of western civilisation, 'critical race theory' and an abandonment of its historical roots in the working class.