The Derbys of Knowsley Hall have been neglected by historians to an astonishing degree. In domestic political terms, the legacies of Disraeli and his Conservative successors have long obscured their Lancastrian aristocratic predecessors. As far as foreign policy is concerned, twentieth century politics and scholarship have often suggested crude polarities: for example, the idea of 'appeasement' versus Churchillian belligerence has its nineteenth century equivalent in Aberdeen's apparent rivalry with Palmerston. The subtleties of other views, such as those represented by the Derbys, have...