Agroforestry systems produce benefits appreciated by farmers, consumers and policy makers alike, including wood for construction and fuel, fruits and medicinal products of many kinds, shade, better soil fertility, erosion and flood control, biodiversity conservation, and carbon sequestration. But implementing agroforestry systems also entails costs — direct costs for labour, management and planting material, as well as indirect costs in the form of foregone opportunities to use the land in ways that could generate higher economic returns or greater levels of ecosystem resilience. Even the most avid fans of agroforestry recognize that such systems are not necessarily the ideal land use for all circumstances or for all functions. There are times and places where pure stands of trees or uniform cropping systems better meet private and social needs. Agroforestry science thus rests on recognizing, measuring, and valuing the tradeoffs inherent in agroforestry systems. Understanding the multiple benefits and costs of agroforestry systems, and fully appreciating the tradeoffs incurred at different social, temporal and spatial scales requires an integrated approach to managing natural resources. This framework — summarized in the following article “Of Sustenance and Sustainability” — serves to organize and inform much of the World Agroforestry Centre’s work.