The prophetic call to inwardness and conscience that emanated from Walden in the 19th would echo at last off the final frontier of the Far West in California. There the wisdom tradition that had its origins in the encounter between Old World civilization and New World Native cultures would go to earth in a new epoch of repentance and the ideal of wilderness. In this Part III, we examine the environmental wisdom of the early 20th century American West by focusing on John Muir and Yosemite Valley in California.