A national holiday in the United States since 1863, Thanksgiving has come to play a number of important roles in popular culture. It was customary in Europe to hold days of thanksgiving both for successful harvests and for events such as military victories, deliverance from plagues, and royal births. The date and site of the first Thanksgiving in what is now the United States are still debated, but the most famous in pre-independence times was that held in October, 1621 in the Plymouth Colony. There, European immigrants, "the Pilgrims," and indigenous Wampanoag Indians celebrated the harvest season with feasting that included the dish that would become a traditional part of the day: turkey. Throughout the colonial era, days of thanksgiving were common, especially in New England, but not universal or regular. Although national days of thanksgiving were proclaimed by the Continental Congress in 1777 and by President Washington in 1789, there was...