In addition to the multiplicity of tribes, the varying lengths of the period of White contact with these peoples should make eastern Bolivia a land of promise for anthropological studies in accultura tion. Some of the Indians came in touch with Spaniards during the first years of the conquest; many were subjected for more than 70 years to Jesuit rule and in?uence; some tribes did not have any contact with the Whites until the rubber boom; others even main tain their independence today and are among the few natives of South America who still live as they did before the arrival of the Whites. In some cases, certain individuals in a tribe have remained culturally unaffected by European customs while some families have been civilized for 2 centuries or longer. The region, therefore, offers an excellent opportunity for a study of culture change.