Secretary of the Smithsonian Institution for 20 years, expert on Indian birds, aviculturist, conservationist, and renaissance man, Sidney Dillon died on 12 March 2001 at the age of 87, following a long and debilitating illness. Known to those who worked for him at the Smithsonian as Mr. Ripley (not Dr., he requested), he was an extraordinary leader and visionary, often inspiring and at times obscure, but always innovative and courageous in his championing of ideas that deserved a hearing, especially to foster the intellectual flowering of his beloved Smithsonian Institution. Dillon was born in New York City on 20 September 1913. His great-grandfather, Sidney Dillon, was founding chairman of the Union Pacific Railroad and in 1869 drove the ceremonial last spike completing the nation's first transcontinental rail line. In 1927, at the age of 13, and his older sister traveled to India. A six-week walking tour into Ladakh and western Tibet led to a lifelong fascination with the Indian subcontinent. In addition, as a teen he fell in love with waterfowl; his book, A Paddling of Ducks (1957), recounts his adventures watching, collecting, owning, breeding, and appreciating ducks, swans, and geese. was educated at St. Paul's School in Concord, New Hampshire, and then at Yale (BA 1936), and Harvard (Ph.D. 1943). His professional career received its first lift in 1936, when, as a recent graduate of Yale, he joined a zoological expedition to New Guinea under the auspices of the Academy of Natural Sciences. Memorialized in his popular Trail of the Money Bird (1942), this two-year voyage gave his first serious taste of tropical ornithology, a love he retained through his life. He worked briefly in the Department of Ornithology at the American Museum of Natural History in New York, and then took his doctorate at Harvard. He served in the OSS in South Asia during the second world war. Returning from the war, taught at Yale, and was a Fulbright fellow in 1950 and a Guggenheim fellow in 1954. He rose to full professor and director of the Peabody Museum of Natural History. During that period of 20 years, he and his colleague Salim Ali of the Bombay Natural History Society redefined the ornithology of the Indian region, and in doing so became the acknowledged authorities on this diverse and now threatened avifauna. Perhaps the capstone of Ripley's scholarship was his Synopsis of the Birds of India and Pakistan (1961), one of the great traditional synoptic checklists of a major avifauna. Better known is Ali and Ripley's 12 volume Handbook of the Birds of India and Pakistan (1968-1974), which has had several lives because of revisions and various ingenious and useful reformulations. As an ornithologist, loved the Old World. Many of his geographically focused works centered on the arc from Pakistan southeastward to the great island of New Guinea, including, in particular, Indonesia, the Philippines, Nepal, and India. He made many expeditions to India and Bhutan with Ali; those constitute a remarkable scientific achievement that may never be equaled. also completed a full revision of the thrushes for Peters' Checklist (1964), as well as a grand monographic treatment of the rails and their allies (Ripley 1977). The latter was an immediate collectible. Lavishly illustrated by J. Fenwick Lansdowne and beautifully designed by Crimilda Pontes, it was one of Time magazine's suggested picks for Christmas shoppers of that year. At that stage in his life, when did something, it was noticed by the popular press as well as the ornithological journals. His high visibility was due to his long tenure (19641984) and conspicuous accomplishments as Secretary of the Smithsonian. Few natural scientists would question the declaration that Dillon was one of the greatest secretaries of the Smithsonian, comparable in effect to Spen-