The letter begins by discussing Iriarte’s admiration for Voltaire’s recent publication of an annotated edition of the works of Corneille. Iriarte notes that he read the translation of la Comedia de Calderon with particular care, before turning to the inadequacies of Spanish theatre. He adds that the King’s senior librarian, Mr. Blas Antiono Nassarre, is printing a version of the comedies of Miguel de Cervantes Saavedera, and that he has enclosed an exemplar of the prologue for Voltaire so that he can understand the history and progress of Spanish theatre and form a fair idea of it. He later adds that he hopes reading this prologue will allow Voltaire to reform the conclusions he made about Spanish theatre in his prologue to his translation of la Comedia de Calderon, which Iriarte suggests has offended the Spanish. Iriarte then defends Spanish theatre at length, in particular the works of Lope de Vega.