Francis Parkman's The Oregon Trail;

Early in his youth, this Boston-born historian was infected with what he called (in language offensive to today's readers) "Injuns on the brain." For the rest of his life, he dedicated himself to writing what he had called at the age of 18 "a history of the American forest." In 1846, following the completion of his studies at Harvard College, he set out in company with a cousin on an expedition from St. Louis over the Oregon Trail to Fort Laramie, Wyoming, a journey that brought him into close contact with the Lakota Indians. Back in Boston, he turned the journal that he had kept on the trail into a series of sketches that were published in the Knickerbocker Magazine and afterwards as a book, The California and Oregon Trail, Being Sketches of Prairie and Rocky Mountain Life (1849), now better known by the abbreviated title of a later revised edition, The Oregon Trail. By this time, Parkman had well underway the historical work that would occupy him during the rest of his life, an account of the French and English in North America, the first installment of which was his History of the Conspiracy of Pontiac and the War of the North American Tribes against the English Colonies, published in 1851.