William E. Doolittle challenges established theories about native agriculture in North America, and puts forward new and innovative ideas. Looking at the evidence from a geographical standpoint, he focuses on fields, field features, and field systems. Emphasis is placed on modifications to the biophysical environment, specifically vegetation, soil, slope, and hydrology. There is a thorough exploration of horticulture, the methods used to maximise the advantages of adequate rainfall, and the techniques developed to compensate for deficits and surpluses in the supply of water. William E. Doolittle uses three types of data: reports on native practices compiled by the early European explorers; ethnographies of the nineteenth and twentieth centuries, which provide ecological information; and archaeological studies, to examine the antiquity and origins of various agricultural activities. The resulting unique and fascinating account of the complexities of native Amreican food production is extensively illustrated with maps, drawings, and photographs. Native agriculture in the rest of the Americas is examined in Cultivated Landscapes of Native Amazonia and the Andes by William M. Denevan, and Cultivated Landscapes of Middle America on the Eve of Conquest by Thomas M. Whitmore and B. L. Turner II.