James Mallord William Turner (1775- 1851) was both the most admired and the most derided painter of his time. His ambition was to excel in all forms of painting and he worked with every possible painterly medium. His vision soon outran the taste of his contemporaries, as he began to experiment in pure forms of light and colour, producing masterpieces of impassioned tonality that were still unsold at the time of his death. Though he travelled widely, he never strayed far from the banks of his home river. He lived by the Thames, in cottages in Hammersmith and Isleworth, and he died by it in a rented house in Chelsea. He was always secretive and kept a mistress about whom little is known. Reputed to be taciturn, miserly, even mad, he was in truth a generous and emotional man who grew tired of the world's attention. Peter Ackroyd's brilliant short biography reveals the genius of the artist and the abiding qualities of the man.