ON 5 NOVEMBER 1994 Ronald Reagan announced in a letter to his fellow Americans that he had Alzheimer's disease, probably triggered by a bad fall from a horse in 1989; and for some years he has ceased to attend those occasions when past presidents muster alongside the current incumbent of the White House. Reagan has retired from active life to his beloved Rancho del Cielo with the same easy-going dignity he restored to the White House, not the least of his remarkable accomplishments.

In Reagan's case, the medium was as important as the message. Since Kennedy and Johnson, US presidents have usually been glimpsed on the telephone rather than thinking, pen in hand. By contrast, Reagan wrote thousands of letters, sometimes during the twenty-minute helicopter ride to Camp David or on longer Air