In principle, the Northwest Amazon includes, as its southern limits, the region from approximately the Middle Amazon, around the mouth of the Rio Negro, to the Upper Solimões; all of the Rio Negro and its northern tributaries, including the Parima mountain range, up to the upper Orinoco Valley; and an arc connecting the Upper Orinoco to the Upper Solimões. Historically, the societies that inhabited this vast region, at least at the time of Spanish conquest in the sixteenth century, were far more numerous than they are today, and far more complex in terms of their social and political organization and interrelations amongst each other. Undoubtedly, their religious organizations and institutions were more complex as well. Sixteenth-century chroniclers left tantalizing notes describing the existence of chiefdoms and priestly societies in the Amazon floodplains region that were similar to those...