Paul Mellon (1907–99) was one of the greatest American philanthropists of the twentieth century and his generosity extended to many different areas, not just the field of studies in British art. Mellon’s extraordinary collection of British art began as an extension of his interest in sporting subjects, first cultivated during his time as a student at the University of Cambridge. However, it rapidly expanded in the 1950s to encompass an encyclopaedic coverage of painting, drawings and watercolours, sculpture, prints and the book arts, which has no equal outside the national collections. In December 1966 he announced the gift of the collection to Yale University with the pledge of a building to house it and an endowment to sustain operations, and this was followed by the creation in London of the Paul Mellon Centre for Studies in British Art, under whose aegis this catalogue has been produced. Advised by the dealer John Baskett, Mellon was a noticeably active collector of British watercolours and drawings, and with Baskett’s aid he was in 1970 able to purchase the bulk of the collection of the artist’s descendant, Tom Girtin (1913–94), including more than a hundred works by or attributed to Girtin. Gifted to the Yale Center for British Art in New Haven, the family collection therefore remained virtually intact, and crucially became more readily available to researchers, amongst whom was Susan Morris, whose 1986 catalogue added much to our understanding of Girtin’s work (Morris, 1986).