Alexis de Tocqueville (1805-59) produced what his biographer Hugh Brogan called ‘the greatest book ever written on the United States’. Among the most remarkable things about this work – Brogan was referring to the first volume of Democracy in America, not the more abstract second volume – is that Tocqueville’s journey to the United States lasted just nine months, and was undertaken when he was in his mid-twenties, never to return.