Bradford Angier is the author of numerous best-selling books on nature and outdoor living, including Field Guide to Medicinal Wild Plants (978-0-8117-2076-2), Wilderness Shelters and How to Build Them (978-1-5857-4430-5), and Looking for Gold (978-0-8117-2034-2). David K. Foster is associate professor of biology and environmental science at Messiah College in Pennsylvania and a member of the Society of American Foresters.