While we lack for Tawantinsuyu the plethora of local studies available for Mesoamerica, we are fortunate to have one comprehensive treat- ment of Indian depopulation that compensates in quality for the dearth of regional mono- graphs. N. D. Cook (1981) uses the term "de- mographic collapse" to describe the fate of "Indian Peru" between 1520-1620. In Cook's study, six different methods are either em- ployed or assessed to estimate the size of "Peru's preconquest population." An ecologi- cal or carrying capacity model produces a figure of 6.5 million. Archaeological data, reflecting the poorly developed status of the field compared to Mexico, are considered too inadequate for any kind of calculation beyond those that are site-specific. Even at this level of analysis, however, problems abound: excava- tion at Chan Chan, Cook notes, yields a range of resident occupants from 25,000-200,000. De- population ratio models, believed by Cook to be unreliable because of problems of statistical sampling, generate 6 million (Rowe 1946), 10 million (Wachtel 1977),12 million (Smith 1970), and 37.5 million (Dobyns 1966), all of which are estimates for the central Andes (Ecuador, Peru, Bolivia). Models of political and social struc- ture, an "idealized concept" with "little basis in fact," give a range of 16-32 million (Means 1931, 1932)