Book excerpt: A biography of a premier French scientist of the Enlightenment and the director of France's Royal Botanical Garden, using Buffon's enormous literary production as the major source of insight into his and his age's beliefs about the natural world. Includes bandw illustrations from his Natural History. First published in 1989 as Buffon, un philosophe au Jardin du Roi, by Librarie Artheme Fayard. Annotation copyrighted by Book News, Inc., Portland, OR