The California and Oregon Trail: Being Sketches of Prairie and Rocky Mountain Life" is a book by Francis Parkman, recounting his 1846 journey across the American West. It's a first-person account of his experiences traveling through Nebraska, Wyoming, Colorado, and Kansas, with a focus on his time spent with the Oglala Sioux. The book is considered a classic work of American literature, offering a vivid portrayal of life on the Oregon Trail and the diverse people encountered along the way.