This book is about post-Pleistocene adaptive change among the aboriginal cultures of the mountains and deserts of Arizona and New Mexico. Conceived essentially as a natural science alternative to the prevailing culture history paradigm, it offers both a general theoretical framework for interpreting the archaeological record of the American South-West and a persuasive evolutionary model for the shift from a hunter-gatherer economy to horticulture at the Mogollon/Anasazi interface. Technical, architectural and settlement adaptations are examined and the rise of matrilineality, ethnic groupings and clans are modelled using ecological and ethnographic data and the innovative idea of anticipated cultural response. In the last part of the book, Dr Hunter-Anderson evaluates the 'fit' between her model and the archaeological record and argues vigorously for research into the evolution of ethnicity in the adaptive context of regional competition.