Crichton pays homage, again, to Arthur Conan Doyle’s The Lost World in this entertaining historical thriller whose manuscript was discovered posthumously. But instead of the living dinosaurs of Jurassic Park, the focus here is on the fossilized ones at the center of the late 19th century’s feud between rival pioneering paleontologists. As in Conan Doyle’s novel, the hero is a callow young man who volunteers for a perilous expedition, headed by an eccentric academic, to prove a point, and grows up in the process. Here, it’s Yale undergraduate William Johnson, who is embarrassed by a classmate’s taunt into a bet that he will spend the summer in a West still populated by hostile Indians. By pretending to be a photographer, Johnson persuades Yale’s Othniel C. Marsh to include him on a fossil hunt. Marsh is worried that Professor Edward Cope, a one-time friend, will try to take credit for his discoveries, and Johnson finds himself dealing with the consequences of their rivalry in a West made even more perilous in the aftermath of Custer’s last stand. Fans of Crichton’s historical suspense books, such as The Great Train Robbery, will be pleased.