Chapter 4 , titled “First Principles,” begins with a discussion of the 1955 conference Man’s Role in Changing the Face of the Earth that was convened to honor the 19th-century statesman and natural historian George Perkins Marsh. This discussion relates the themes of progress and environmental destruction advanced by Marsh in Man and Nature to ideas McHarg subsequently explored in the seminar course Man and Environment, including his decision to divide the course into sections devoted to ecology, religion, and stewardship — the trinity of subjects that defined his vision of design with nature. The lectures given by Robert MacArthur on ecology, Morse Peckham on the concept of nature in Western garden traditions, and Paul Sears on the importance of ecology in land conservation and stewardship structure this discussion.