James Mallord William Turner has been termed England's greatest painters. In a career that spanned the late eighteenth century and the first half of the nineteenth, he painted landscapes - luminous, mystic visions of nature - that forecast some of the most avant-garde of twentieth-century panting, frequently leaping beyond the Impressionists. The treatment of light in Turner's work, seen especially in the lemons, golds and rusts of his sunrises and sunsets or in the blues of his seas and mountains, has captivated generations of art lovers.