This text continues the tale started in Hemming's Red Gold. This book covers the 150 years when the first European scientists explored Amazonia and were fascinated by its tribal people. Encounters with new tribes continued throughout the 19th century, particularly when the Amazon's rubber monopoly made Manaus a frontier boom town, but the Indians declined drastically in numbers, and changed from being feared enemies to objects of anthropological study or romantic literature. Amazon Frontier ends in 1910 with the creation of Brazil's Indian Protection Service and an illusion of a new ear of tolerance of its native peoples.