James Lighthill died on 17 July 1998, at the end of a ten-hour swim round the Channel Island of Sark. He had earlier, at age 49, been the first person ever to do this, and he was carrying out the swim for the seventh time when the exertion revealed a mitral valve weakness which had never been diagnosed, and which led to his sudden death in the water. The swim was one of many long ‘adventure swims’ which Lighthill liked to take, all characterized by strong tidal currents and often heavy seas. And Lighthill took much pleasure through exercising his comprehensive understanding of fluid mechanics first in preparing for them through study of local conditions and then in adapting his performance when, as often, he found that in practice the currents were not as charted and, in fact, often more treacherous.

Many obituary notices have already appeared in the national press in the UK and USA, and now in the newsletters and journals of learned societies; and extensive conspectuses of Lighthill's contributions to fluid mechanics and applied mathematics, and to science generally and to the administration of science, will be published in Annual Review of Fluid Mechanics (2000), and in Biographical Memoirs of Fellows of the Royal Society (2000). The reader will learn, from those accounts, of the unique range and depth of Lighthill's contributions; and virtually all readers should expect to be surprised and impressed to read of facets of Lighthill's work of which they were previously totally unaware.