Understory plants and fungi are critical to healthy and resilient forest ecosystems, and many of the products they provide are essential to people for sustenance and income. However, nontimber forest products, and the plants and fungi from which they originate, are seldom included in forest management. Most are harvested from natural populations, with potential for negative impacts at multiple ecological scales. This chapter introduces sustainable use of nontimber forest resources and describes methods for assessing product inventory and recovery. The chapter explains how traditional and local ecological knowledge is important in understanding how people steward the resources and production of nontimber products, with implications for sustainable management. The chapter provides detailed case studies of three North American edible and medicinal forest species. Finally, the chapter considers research priorities and future trends in this area, and provides guidance on further reading on this subject.