Bones of the Earth (2002) by Michael Swanwick

Modern technology is pitted against ancient dinosaurs in this scientific thriller James Rollins calls " Jurassic Park set amid the paradox of time travel."

Paleontologist Richard Leyster is perfectly content in his position with the Smithsonian excavating dinosaur fossil sites and publishing his findings . . . until the mysterious Harry Griffin appears in his office with a cooler containing the head of a freshly killed Stegosaurus. The enigmatic stranger offers Leyster the opportunity to travel back in time to study living dinosaurs in their original habitats—but with strings attached.

Soon, the paleontologist finds himself, along with a select team of colleagues—including his chief rival, the ambitious and often ruthless Dr. Gertrude Salley—making discoveries that would prove impossible working from fossils alone. But when Leyster and his team are stranded in the Cretaceous, they must learn to survive while still keeping alive the joy of scientific discovery. This shocking novel spans hundreds of millions of years and deals with the ultimate fate not only of the dinosaurs but also of all humankind.

Nominated for the Locus Award, the Hugo Award, and the Nebula Award for Best Novel, Bones of the Earth cements author Michael Swanwick as an author who "proves that sci-fi has plenty of room for wonder and literary values" ( San Francisco Chronicle ).