Alwin, John A. Eastern Montana: A Portrait of the Land and Its People. Montana Geographic Series, no. 2. Helena [1]: Montana magazine, 1982. A broad overview of the people, sights, and regions of eastern Montana, in text and photos.
Federal Writers’ Project of the Work Projects Administration for the State of Montana. Montana: A State Guide Book. State of Montana: Department of Agriculture, Labor, and Industry, 1939. New York: Hastings House, 1949. Long out of print, but it’s worth snaring a copy at a used-book store.
Gildart, R. C., ed. Glacier Country: Montana’s Glacier National Park [2]. Montana Geographic Series, no. 4. Helena [1]: Montana magazine, 1990. An introduction to Glacier Park and its natural history, with ample illustrations and intelligent text.
Gildart, R. C. Montana’s Flathead Country. Montana Geographic Series, no. 14. Helena [1]: Montana magazine, 1986. Colorful histories, a look at the environment, and splendid photos define the area around Flathead Lake [3].
Gildart, R. C. Montana’s Missouri River. Montana Geographic Series, no. 8. Helena [1]: Montana magazine, 1985. Text and photographs celebrate the Wild and Scenic Missouri.
Meloy, Mark. Islands on the Prairie: The Mountain Ranges of Eastern Montana. Montana Geographic Series, no. 13. Helena [1]: Montana magazine, 1986. Pictures and text about the often-ignored mountains in eastern Montana.
Mullan, John. Miners and Travelers’ Guide to Oregon, Washington, Idaho, Montana, Wyoming, and Colorado via the Missouri and Columbia Rivers. 1865. New York: Arno Press, reprinted 1973. One of the earliest travel guides to the region, filled with colorful stories of the opening of the West.
Schneider, Bill. Montana’s Yellowstone River. Montana Geographic Series, no. 10. Helena [1]: Montana magazine, 1985. An enthusiastic portrait of the Yellowstone River, with a strong conservationist cast.
Tirrell, Norma. Montana. Oakland, Calif.: Compass American Guides, 1991. An easy-reading and attractive guide that provides a good overview of Montana sights and culture.
Links:
[1] http://www.moon.com/destinations/montana/butte-helena-and-southwestern-montana/helena
[2] http://www.moon.com/destinations/montana/glacier-national-park
[3] http://www.moon.com/destinations/montana/missoula-and-northwestern-montana/flathead-lake