Admired long after his death by the likes of Lord Rayleigh and Einstein, Thomas Young (1773-1829) was the definition of a polymath. By the age of fourteen he was proficient in thirteen languages, including Greek, Hebrew and Persian. After studies in Edinburgh, London, Göttingen and Cambridge he established himself as a physician in London, and over the course of his life made contributions to science, linguistics and music. He was the first to prove that light is a wave rather than molecular, his three-colour theory of vision was confirmed in the twentieth century, and his work in deciphering the Rosetta Stone laid the foundations for its eventual translation. Published in 1855, this engaging biography drew on letters, journals and private papers, taking the mathematician George Peacock (1791-1858) twenty years to complete. It stands as a valuable and affectionate portrait of 'the last man who knew everything'.