The book presents recent research findings in different fields that suggest human populations in the Western Hemisphere—that is, the Indigenous peoples of the Americas—were more numerous, had arrived earlier, were more sophisticated culturally, and controlled and shaped the natural landscape to a greater extent than scholars had previously thought. The author notes that, according to these findings, two of the first six independent centers of civilization arose in the Americas: the first, Norte Chico or Caral-Supe, in present-day northern Peru; and that of Formative-era Mesoamerica in what is now southern Mexico.