In the winter of 2008, the Penn Museum International Research Conference series sponsored a 4-day symposium, "Forces of Nature: Risk and Resilience as Factors of Long-term Cultural Change." We gathered specialists working in at least one of four areas of the world with significant archaeological and paleoenvironmental databases: West Asia, the American Southwest, East Africa, and Andean South America. The participating scholars have made contributions to research within at least one of three broad time scales: long-term (spanning millennia), medium-term (archaeological time--centuries or a few thousand years), and recent (ethnohistoric or ethnographic--years or decades). Thisvolume addresses forces of conservatism and innovation at work in societies dependent on the exploitation of aquatic and other wild resources, agriculture, and specialized pastoralism. By bringing an archaeological eye to an examination of human response to unpredictable environmental conditions, informed by an understanding of contemporary traditional peoples, the symposium participants attempted to develop a nuanced picture of how societies perceive environmental risk, how they alter their behavior in the face of changing conditions, and under what challenges the most rapid and far-reaching changes in adaptation have taken place.