Noisy popular liberal interventionism? Or a more conservative, diplomatic approach concentrating on co-operation between nations? This is the debate that lies at the heart of modern politics and Hurd traces its most interesting and influential exponents. He starts with Canning and Castelreagh in post Waterloo Britain; to a generation later, the victory of the interventionist Palmerston over Aberdeen; then to Salisbury (Imperialism) and Grey (European...