One of the richest and most complex civilizations in ancient America evolved around Lake Titicaca in southern Peru and northern Bolivia. This book is a comprehensive synthesis of four thousand years of prehistory for the entire Titicaca region. It is a story of the transition from hunting and gathering to early agriculture, to the formation of the Tiwanaku and Pucara civilizations, and to the double conquest of the region, first by the powerful neighboring Inca in the fifteenth century and a century later by the Spanish Crown. Based on more than fifteen years of field research in Peru and Bolivia, the book brings together a wide range of ethnographic, historical, and archaeological data, including material not previously published. It brings together intimate knowledge of the ethnography and archaeology in this region to bear on major theoretical concerns in evolutionary anthropology. The book provides a broad comparative framework for evaluating how these complex societies developed. After giving an overview of the region's archaeology and cultural history, it discusses the history of archaeological research in the Titicaca Basin, as well as its geography, ecology, and ethnography. The book then synthesizes the data from six archaeological periods in the Titicaca Basin within an evolutionary anthropological framework. Titicaca Basin prehistory has long been viewed through the lens of Inca intellectuals and the Spanish state. This book demonstrates that the ancestors of the Aymara people of the Titicaca Basin rivaled the Incas in wealth, sophistication, and cultural genius.