William Cronon is the author of Nature’s Metropolis: Chicago and the Great West published in 1991. Cronon is an environmental historian, writer, and professor specializing in the history of the American West and the human relationship to the natural world. He served as the president of the American Society for Environmental History from 1994 to 2014.

Cronon’s best-known work is 1983’s Changes in the Land: Indians, Colonists, and the Ecology of New England. In it, he discussed how an economy is shaped by its participants’ attitudes toward property rights, which in turn affects the ecology of the surrounding area.

In a New York Times article, journalist Janny Scott credits Cronon with “having radically widened many environmental historians’ gaze beyond such things as forests and public lands to include cities and what Cronon calls the ‘elaborate and intimate linkages’ between city and country” (Scott, Janny. “An Environmentalist on a Different Path; A Fresh View of the Supposed ‘Wilderness’ and Even the Indians’ Place in It.” New York Times. 3 Apr. 1990).

Frederick Jackson Turner is a 20th-century historian and professor best known for his frontier thesis. His most well-known essay, “The Significance of the Frontier in American History,” presented the theories that would eventually shape the thesis.