In this issue we present the second part of the special section on recent research on Late Aztec Otumba, Tepeapulco, and Teotihuacan by Thomas H. Charlton, Deborah L. Nichols, Cynthia L. Otis Charlton, and their colleagues. The background to this research was discussed by those authors in our previous issue (Charlton, Nichols, and Otis Charlton 2000), and, as I pointed out in the introduction to the first part (Fowler 2000), a distinct advantage provided by the Otumba research is that the data generated allow us to assess general models proposed for the origin and development of city-states in the Basin of Mexico during the last few centuries before the Spanish Conquest. To summarize briefly, two general models have been proposed—one emphasizing economic symbiosis and craft specialization and the other focusing on regional political competition among elites. The Otumba data and analyses allow us to perceive and explore further valid aspects of both models.