The controversy over the Columbian Quincentenary identifies two broad issues of fundamental interest to geography: (a) the decimation and displacement of indigenous peoples, leading to creation of new human and cultural landscapes; and (b) the relative ecological impacts of indigenous and Colonial land use, as a prelude to the global environmental transformation introduced by the Industrial Revolution. This introductory essay outlines the contributions of ten critical or synthetic reviews, setting them in a wider context of contemporary research, as a web of related themes focused on the Americas before and after 1492. These themes include: (a) pre-Columbian population densities, environmental impact, and the myth of the Indian as Ecologist; (b) the labor intensity and technological sophistication of pre-Columbian agriculture in many areas; (c) the human implications and landscape impact of catastrophic indigenous depopulation; (d) the process of Spanish settlement and landscape transformation; (e) diffusion, continuity, and syncretism in the residual indigenous landscapes; (f 1 the divergent