Boller was a fur trader among the "savage tribes of the great plains on the upper Missouri" for eight years, and Field feels this "enabled him to form his judgement on solid experience" in portraying the Native Americans of that region. Adams notes mention of the vigilantes of Montana and the hanging of Henry Plummer, and states that "most of the existing copies of this rare book lack the map." As noted by Wheat, the map "displays Montana, the absurdly extended Dakotah, Nebraska, and parts of Idaho, Utah, Colorado, Kansas and Missouri. The map is notable mostly for the localities mentioned along the course of the Missouri... No trails or wagon roads are represented, but the two Union Pacific roads out the Platte [sic] and Smoky Hill are shown - the main Union Pacific indicated as going to Great Salt Lake City, then north around Great Salt Lake." Adams Six-guns 235; Field 147; Flake 582; Howes B579; Sabin 6221; Smith 928; Wheat Transmississippi 1180.