Mrs Thatcher divided the political nation into those who were passionately in favour of her and those who were passionately against. It has never been easy for either side to cultivate historical detachment but Richard Vinen thinks it is high time that we all began to do so. His appeal is addressed with special force to those who, like himself, were on the Left throughout the Thatcher years. ‘I have often felt exasperated’, he writes, ‘by the partisan nature of writing on this subject and particularly by the sneering tone many authors adopt with regard to Margaret Thatcher herself.’ His own treatment of her, by no means uncritical, emphasises the gulf between the caricature of dotty right-wing extremist and the pragmatism and caution she so often displayed. Biography, however, is incidental to Vinen’s main purpose, which is to define the nature of ‘Thatcherism’ – the constellation of ideas, policies and values that came to be associated with her. His book, which is beautifully written with great wit and finesse, helps us to think straight about an era of visceral prejudice.