Pierre Clastres (French: [pjɛʁ klastʁ]; 17 May 1934 – 29 July 1977) was a French anthropologist, ethnographer, and ethnologist. He is best known for his contributions to the field of political anthropology, with his fieldwork among the Guayaki in Paraguay and his theory of stateless societies. He mostly researched Indigenous peoples of the Americas in which the power was not considered coercive and chieftains were powerless.
With a background in literature and philosophy, Clastres started studying anthropology with Claude Lévi-Strauss and Alfred Métraux in the 1950s. Between 1963 and 1974 he traveled five times to South America to do fieldwork among the Guaraní, the Chulupi, and the Yanomami.
Chronicle of the Guayaki Indians is Pierre Clastres's account of his 1963-64 encounter with this small Paraguayan tribe, a precise and detailed recording of the history, ritual, myths, and culture of this remarkably unique, and now vanished, people. "Determined not to let the slightest detail" escape him or to leave unanswered the many questions prompted by his personal experiences. Clastres follows the Guayakis in their everyday lives.