It is possible to appreciate the unique contribution of the third Marquess of Salisbury to English, British (a word he did not use) and world history, without sharing his principles’, as he judged them to be, principles which were often no more than opinions, sometimes no more than prejudices. Some of the opinions were cast aside as he transformed himself from a politician into a statesman. Yet there were abiding principles which survived. They transcended party, although, as Andrew Roberts shows in this long-awaited and meticulously researched biography, Salisbury, intelligent as well as principled, made democracy, which he despised, work for the Conservative Party. During the last decades of the nineteenth century he discovered in the ‘new suburbia and lower middle classes a whole new area of support for his brand of Tory Unionism’.