The life of Sir William Hamilton is rich in contradictions: hedonist, scholar and an aesthete with a Rabelaisian streak, he represented the epitome of honourable public service until, as the eighteenth century drew to its climax, his personal life and career were flung into freefall when he became involved in the most scandalous menage a trois of the century. After several years as a soldier, courtier and MP, he turned to the diplomatic world and, in 1764, was sent to Naples as Envoy Extraordinary to the Kingdom of the Two Sicilies. There Hamilton could indulge the two passions: volcanoes and vases. His observations of Vesuvius earned him a Fellowship of the Royal Society. His collection of vases was eventually acquired by the British Museum. Yet, for most people, William Hamilton is not remembered as a diplomat, art-collector and scholar but as the cuckolded husband of Emma Hamilton, mistress of the heroic Lord Nelson. Using the substantial correspondence between them and, for the first time, Hamilton's unpublished notebooks, David Constantine throws new light on the relationship between Sir William and the relentlessly self-improving Emma.