The Overland Emigrants and the Trans-Mississippi West, 1840-1860
this is an exhaustive compendium of research on the overland emigration for the entire 1840-1860 period. the author also developed an hypothesis, "applying the concept of change through time" based on the "...interactions of overlanders and other groups in the West... with the flora and fauna of the West."
This 2nd edition was edited, after the death of the author, to reflect the kinds of edits usually taken before a dissertation is published. Edition deleted the material that is primarily of interest to the professional historian, and edited to make the book more accessible to students and other interested readers.
by John D Unruh, Jr
University of Illinois Press, 1982