The Big Sky is a 1947 Western novel by A. B. Guthrie Jr. It is the first of six novels in Guthrie's sequence dealing with the Oregon Trail and the development of Montana from 1830, the time of the mountain men, to "the cattle empire of the 1880s to the near present." The first three books of the six in chronological story sequence (but not in the sequence of publishing) – The Big Sky, The Way West, and Fair Land, Fair Land – are in themselves a complete trilogy, starting in the 1830s and ending in the 1870s. Source: Wikipedia (en)