Indeed, they were not what they seemed. They were two brothers named Frank and Theo Molina and their friend Arden Scofield. A trio of adventurous, young Americans, they had no interest in hayos, the coca-leaf gardens that the people of the Amazon had grown for a thousand years but were now deemed unlawful by the Peruvian government. All three were promising Harvard graduate students in ethnobotany, the study of how the world’s peoples make use of local plants for food, drugs, medicine, clothing, and anything else. Since getting their bachelor’s degrees, Arden and Theo had continued at Harvard, working toward their master’s degrees, with specializations in South American flora. They had arrived in the Amazon only ten days earlier. Frank Molina – six years older than his brother and five years older than Arden and the most serious scholar of the three – had been living in Iquitos for the past ten months, completing the fieldwork for his Ph. D. dissertation on the Amazonian Indians’ use of Brunfelsia grandiflora, a member of the potato family, for curing gum disease.

But it was not this plant that these ambitious young men were after, nor any other medicinal botanical. It was Hevea brasiliensis – the rubber tree, and through it they meant to make a great deal of money.

In all its existence, the Amazon had known something resembling prosperity but once: during the rubber boom of the late 1800s, when the strange, new, bouncy substance was king. The finest rubber in the world came from Amazonian trees, and huge fortunes were made in the rowdy, knockabout jungle towns at either end of the great Amazon river, Manaus, Brazil and Iquitos, Peru. But the seeds of ruin – the literal seeds – had already been sown. An English botanist named Henry Wickham had smuggled seventy thousand seeds out of South America in 1870 and gotten them to Malaysia. Five years later, the new plants were being tapped, and in thirty years they had become great trees superior even to those of the Amazon. By 1913, Malaysia and Singapore were the new capitals of the rubber market. The Amazonian boom had gone bust.