"The Essex Serpent" is a historical novel by Sarah Perry set in the late 19th century. It follows the story of Cora Seaborne, a widow who moves to the village of Aldwinter in Essex to investigate reports of a mythical creature, the Essex Serpent. As she explores the local folklore, she becomes entangled in the lives of the villagers, including Will Ransome, a local vicar. The novel delves into themes of science, belief, and the clash between rationality and superstition. It also examines the complexities of human relationships and the impact of societal expectations on personal freedom.