El castigo sin venganza (1631) is Lope de Vega's greatest tragedy. The play dramatises the story of the adulterous relationship between the beautiful Casandra, Duchess of Ferrara, and her step-son, Federico, and the reaction of her husband, the Duke, himself a flawed and ambiguous figure. The dramatist, at the height of his powers, re-works an earlier Italian short story to explore the complexities of human desire and the grim consequences of giving in to temptation. Aimed principally at undergraduates who are new to Spanish Golden Age drama, this edition includes a substantial commentary on the text, explanatory footnotes and a selected vocabulary. The introduction sets the play in its contexts - historical and dramatic - and focuses too on elements of the genre with which new readers might be unfamiliar: performance norms, the poetry of the play and the linguistic differences in Golden Age Spanish.