The fascinating tale of the excavation and analysis of the longest and perhaps heaviest dinosaur known to science. Gillette begins his story with the serendipitous 1979 discovery of several large bones by two hikers in the New Mexico desert. At the time curator of paleontology at the New Mexico State Museum of Natural History, Gillette was put in charge of unearthing the skeleton. After excavating eight tail vertebrae, he realized they didn't match those of any known dinosaur genus. He affectionately dubbed his animal ""Sam"" and named the new genus Seismosaurus, Latin for ""Earth-shaking lizard"" -- rather appropriate for a 150-foot-long, 100-ton behemoth. Seismosaurus was a sauropod, the infraorder of dinosaurs that includes the Brachiosaurus of Jurassic Park fame. Most of Sam's bones were so deeply embedded in sandstone that Gillette solicited help from scientists at the nearby Los Alamos National Laboratory. The result, he explains, was the first experiment in ""high-tech paleontology,"" as scientists tried to pinpoint bone inside solid rock with such gizmos as ground-penetrating radar and magnetometers. These methods were only partially successful, and Gillette emphasizes that the bulk of the work still involved low-tech hammers, picks, and shovels. The resulting seven-year dig revealed a wealth of bones and 240 plum-sized stones that may have stirred digestive juices in Sam's gut. The second half of the book is devoted to scientific analysis of the fossils and the mysterious process of fossilization. While Gillette neglects to shed much light on the hottest dinosaur controversies, such as their warm- or cold-bloodedness and their evolutionary link to birds, he covers a dazzling range of topics related to dinosaur paleontology. Most important, he sticks primarily to the facts and lets the reader know when he engages in speculation. Fast-paced, almost conversational, and particularly enjoyable for dinosaur buffs.