Some of the most enduring and fundamental questions in archaeology relate to site seasonality. During which seasons did people occupy coastal archaeological sites? Why is "seasonality" important to our understanding of human behavior? What does this knowledge tell us about life in dynamic estuarine systems? What methods and technologies are available to address key issues of seasonality? Archaeological seasonality is uniquely linked to settlement patterns, resource availability, environmental relationships, anthropogenesis, landscapes, and social complexity. Archaeologists working in coastal settings typically recover multiple biological proxies that are well suited to explicating questions of human seasonal behavior. The Fifth Caldwell Conference was convened to discuss and report on practiced methods for reading the seasonality record found in common biological proxies. These researchers spoke of how they are applying various methods grounded in the natural sciences to estimate seasonality with particular reference to the archaeology of St. Catherines Island and the Georgia Bight. These methods include stable isotope analysis, ¹⁴C dating, longitudinal studies of animals (molluscs and fishes), zooarchaeology, and archaeobotany. The research shows that all plant and animal remains found in a midden contain a record of human behavior. The authors of these 13 chapters agree that multiple indicators of site seasonality provide the most robust picture of the annual settlement cycle. These papers were initially presented at the Fifth Caldwell Conference, cosponsored by the American Museum of Natural History and the St. Catherines Island Foundation, held on St. Catherines Island, Georgia, May 14-16, 2010.