American Publishing Co. published Mark Twain's Innocents Abroad the same year. It was Richardson's previous account of his capture by the Confederacy in the Civil War that prompted Twain to start working with American Publishing and move to Hartford.

More than 200 Illustrations, from Photographs and Original Sketches, of the Prairies, Deserts, Mountains, Rivers, Mines, Cities, Indians, Trappers, Pioneers, and Great Natural Curiosities of the New States and Territories from 1857 - 1867. A vivid account of the slavery battles in Kansas and Missouri, rare encounters with Indian tribes, and travel to the Pacific Coast before the Civil War. A trip from Sacramento to Salt Lake at the invitation of CPRR President Leland Stanford to inspect the on-going construction of the line; along with visits to many towns and mining camps throughout the American West. Excellent chapter on Yosemite.

The book is much in the style of Twain's Roughing It, issued several years later and similarities exist. Richardson had been a correspondent for Horace Greeley's New York Tribune and knew Greeley well. On page 382 in "Beyond The Mississippi", Richardson wrote about Greeley's famous ride with Hank Monk. The story is barely two pages in length, but it was written a full five years before Twain dressed it up a bit and published it in "Roughing It" in 1872. Researcher and author Beverly David documents four instances where "Beyond The Mississippi" etchings were used in "Roughing It."