Some National Geographic magazine assignments come out of the blue. A phone call or email from an editor saying, “Can you go to the Amazon for us next month?” They can take shape quickly, and be carried out and completed in months. Then there are the ones that span half a lifetime. This is one of those.

It was in 1986 when I saw the poster in the hall of the biology building at Harvard. It featured a plate from Alfred Russell Wallace’s natural history classic The Malay Archipelago: Land of the Orangutan and the Bird of Paradise, depicting Dayak natives in Borneo battling a giant orangutan. “Wanted: Field Assistants for Rain Forest Research in Borneo. Contact Prof. Mark Leighton,” or