Papers in this Special Feature were presented at a symposium on the biology of Glaucomys sabrinus convened at the 86th Annual Meeting of the American Society of Mammalogists in June 2006. Because G. sabrinus is an arboreal species that relies on several attributes of older forests, it is an ideal model organism for studying impacts of broad-scale habitat loss and alteration from logging, clearing, and natural disturbances. The objective of the symposium was to integrate knowledge of mammalogists from multiple disciplines to achieve a more complete biological portrait to gain insights about how forest communities are being impacted by dramatic changes in forest composition and distribution following European settlement of North America, and to identify gaps in knowledge and information needs that can guide future research. The symposium included 5 papers that encompass a diversity of biological information, including the evolutionary origin and systematics of Glaucomys, the anatomy and evolution of G. sabrinus, its biogeography, genetic variation within and among regional populations, its ecology, functional morphology, kinetics, and issues and challenges of conservation.