John Fletcher and Philip Massinger's comedy Love's Cure, or The Martial Maid (1615) is an innovative and provocative play that explores the struggle of two transgender siblings, Lucio and Clara, who have been brought up as members of their opposite genders. After twenty years of separation, they are forced to switch around their gender identities, facing fierce scrutiny from their family and the cruelly heteronormative society of early modern Seville. This Revels Plays volume is the first fully annotated, single-volume critical edition of the play ever to be published. The text has been modernised and is accompanied by full commentary. The introduction presents ground-breaking research on the play's remarkable engagement with its Spanish literary sources, and it provides a full discussion of its dating, authorship, and reception by literary critics and in the theatre.