A group of local men, camped near their fishing nets along the beach, greeted the Goodall party and helped bring up the gear. Jane and her mother spent the afternoon putting their camp in order. Then, around 5 p.m., somebody reported having seen a chimpanzee. "So off we went," Jane wrote later that night in her journal, "and there was the chimp." She had gotten only a distant, indistinct glimpse. "It moved away as we drew level with the crowd of fishermen gazing at it, and, though we climbed the neighbouring slope, we didn't see it again." But she had noticed, and recorded, some bent branches flattened together in a nearby tree: a chimp nest. That datum, that first nest, was the starting point of what has become one of the most significant ongoing sagas in modern field biology: the continuous, minutely detailed, 50-year study, by Jane Goodall and others, of the behavior of the chimps of Gombe.

Science history, with the charm of a fairy-tale legend, records some of the high points and iconic details of that saga. Young Miss Goodall had no scientific credentials when she began, not even an undergraduate degree. She was a bright, motivated secretarial school graduate from England who had always loved animals and dreamed of studying them in Africa. She came from a family of strong women, little money, and absent men. During the early weeks at Gombe she struggled, groping for a methodology, losing time to a fever that was probably malaria, hiking many miles in the forested mountains, and glimpsing few chimpanzees, until an elderly male with grizzled chin whiskers extended to her a tentative, startling gesture of trust. She named the old chimp David Greybeard. Thanks partly to him, she made three observations that rattled the comfortable wisdoms of physical anthropology: meat eating by chimps (who had been presumed vegetarian), tool use by chimps (in the form of plant stems probed into termite mounds), and toolmaking (stripping leaves from stems), supposedly a unique trait of human premeditation. Each of those discoveries further narrowed the perceived gap of intelligence and culture between Homo sapiens and Pan troglodytes.

The toolmaking observation was the most epochal of the three, causing a furor within anthropological circles because "man the toolmaker" held sway as an almost canonical definition of our species. Louis Leakey, thrilled by Jane's news, wrote to her: "Now we must redefine 'tool,' redefine 'man,' or accept chimpanzees as humans." It was a memorable line, marking a very important new stage in thinking about human essence. Another interesting point to remember is that, paradigm shifting or not, all three of those most celebrated discoveries were made by Jane (everyone calls her Jane; there is no sensible way not to call her Jane) within her first four months in the field. She got off to a fast start. But the real measure of her work at Gombe can't be taken with such a short ruler.