The Exploration of the Colorado River and Its Canyons (Penguin Classics)
John Wesley Powell (1834-1902) was a professor of geology and director of the U.S. Geological Survey.Wallace Stegner (1909-1993)  was the author of numerous works of fiction and non-fiction, including the National Book Award-winningThe Spectator BirdandAngle of Repose, which won the Pulitzer Prize.