Across the Wide Missouri, With an Account of the Discovery of the Miller Collection is a 1947 nonfiction history book by American historian Bernard DeVoto.

The chronology is sometimes confusing, but the book contains a lively if somewhat romanticized portrayal of the way of life of the individual trappers known as Mountain Men, who were the RMFC's main suppliers and customers, with less attention given to the organized "brigades" of American Fur.

The book is well researched and documented, using original sources from the people involved, such as personal diaries, letters, journals, notes, and conversational accounts.

Devoto’s opinions on the cultures of the various Native American tribes and their relations with the Mountain Men are based on these sources, and may not meet current standards of political correctness, but he does not corrupt history by cutting “his trail through an undergrowth of twentieth century ideas projected backward, usually with indignation.” (P298) He portrays the trappers' attitudes toward race and gender as they were, without judgment, including the practical necessity for the independent trapper to purchase a Native American wife from her family to help make camp and process pelts, a common transaction also practiced by the Native American tribes themselves.

DeVoto points out that the RMFC pioneered overland wagon transport across the Great Plains, and that the knowledge of the interior West gained by the Mountain Men played an essential role in the overland migrations to California and Oregon in the 1840s, with many of the former trappers working as scouts and guides after the fur trade collapsed due to over-hunting of beaver and changes in fashion.