Uncontacted Tribes

Uncontacted tribes are groups of aboriginal people who still live as their ancestors did.
They have chosen to maintain their traditional lifestyles, even after encounters with other tribal groups who do interact with the modern world.  An increasing number of these tribes have been having devastating encounters with various groups (illegal loggers, rubber companies, oil corporations, mining concerns) that are after their lands.  In some countries, they live in reservation land set aside by the government to live independent of outside harassment and encroachment.  In other countries, the government officially claims to protect the rights of these groups, but in actuality consider them a nuisance because they occupy lands that are rich in natural resources that governments and corporations see as an untapped source of revenue.

Although they are called 'uncontacted', researchers know that they exist but these tribal groups choose to have little to no contact with the 'modern' world.

http://www.uncontactedtribes.org/
http://www.amazon-indians.org/Uncontacted-Amazon-Indians-Peru.html
http://www.survivalinternational.org/tribes/isolatedperu