Boston-born and Harvard-educated, Richard evans Schultes is Jeffrey Professor of Biology and Director of the Botanical Museum of Harvard University (Emeritus). Botanical explorer, ethnobotanist and conservationist, he has carried out extensive field studies, particularly in the Amazon, since 1939, specialising on natively used medicinal and toxic plants and on new sources of rubber. Among his numerous awards are the Cross of Boyaca, Colombia's highest honour, and the annual Gold Medal of the World Wildlife Fund, presented by H.R.H. the Duke of Edinburgh. In 1987, he received the prestigious Tyler Prize for Environmental Achievement; and in 1992, he was awarded the Linnean Gold Medal, the highest award a botanist can receive. Dr. Schultes is a member of the National Academy of Sciences, the American Academy of Arts and Sciences, the Linnean Society of London, three Latin American academies, the Academy of India, and Third World Academy of Sciences.

Robert F. Raffauf is Professor of Pharmacognosy and Medicinal Chemistry (Emeritus) at the College of Pharmacy and Allied Health Professions of Northeastern University in Boston. Dr. Raffauf has spent twenty-five years in the pharmaceutical industry concentrating on the search for novel medicinal agents from natural sources, part of which included several expeditions to the Amazon with Dr. Schultes and his students. Dr. Raffauf is a member of several professional and academic honour societies, a Fellow of the Linnean Society of London, and the American Association for the Advancement of Science, and a Research Associate of the Botanical Museum of Harvard University.