Djaja D. Soejarto has been trekking through the rain forests of Laos and Vietnam for over two decades in search of cytotoxic molecules—the anticancer drugs of the future.

It's a quest—a biological prospecting—that depends on carefully-crafted partnerships with national governments, village communities, and local healers.

"The community has to know what we intend to do. They have to permit us to go in there," Soejarto told The Daily Beast. "When you want to sit down with the [traditional] healer, before you ask any questions, you have to ask permission to the healer whether he or she wishes to be interviewed."