Hercules is the best-known character from classical mythology. Seneca's play Hercules Furens presents the hero at a moment of triumph turned to tragedy. Hercules returns from his final labor, his journey to the Underworld, and then slaughters his family in an episode of madness. This play exerted great influence on Shakespeare and other Renaissance tragedians, and also inspired contemporary adaptations in film, TV, and comics. Aimed at undergraduates and non-specialists, this companion introduces the play's action, historical context and literary tradition, critical reception, adaptation, and performance tradition.