The subject of this article is Indian society in the Pampas and neighbouring territories in Argentina. I will focus on the deep changes that Indian societies experienced in their economy and socio-political structure during the period that followed Hispanic settlement on the Río de la Plata shores at the end of the sixteenth century. The original hunter-gatherer bands had transformed into true chiefdoms by the middle of the nineteenth century. How, when, and why they changed are the questions that I, and other scholars in Argentina, have tried to answer.