Marsh, who is remembered today for his contributions to ecology in his book, Man and nature, was appointed by president Zachary Taylor  United States minister resident in the Ottoman Empire from 1849-1854. There he undoubtedly became familiar with camels, and believed that there would be economic and other benefits of introducing the camel into the United States. His book covers a broad range of issues relating to the camel, including breeds, diet, diseases, temperament and training. Marsh also includes a chapter on the military uses of the camel, which he felt was perfectly suited for the warfare of his day. According to Marsh, the camel "is a much less timid animal than the horse or mule." He also believed that riding a camel offered a better range of vision, because it is two feet higher than the horse. Digital facsimile from the Internet Archive at this link.

“The fountainhead of the conservation movement” (Mumford). This is a comprehensive scientific account of humanity's enormous and often destructive impact on the physical world. Marsh warned of the dangers of the reckless misuse of land then endemic in the United States, using the ruined lands of the Mediterranean region as an example of America’s probable future, and called for a scientific program to restore the land. Reprint edited by David Lowenthal, Cambridge, Mass: Harvard University Press, 1965. Reprint of the 1965 edition with a foreward by William Cronon and a new introduction by David Lowenthal, Seattle: University of Washington Press, 2003. Digital facsimile of the 1864 edition from the Internet Archive at this link. Revised second edition retitled The earth as modified by human action (1874). Digital facsimile of the second edition from Biodiversity Heritage Library at this link.