This is the first publication of Un avvertimento ai gelosi (1831), a one-act “salon opera” for six singers and piano by Manuel del Pópulo Vicente Rodríguez García (1775–1832). Renowned as one of the leading tenor virtuosos of his generation, García was also an esteemed teacher who shared valuable bel canto techniques with his students, including his famous children, Maria Malibran, Pauline Viardot, and Manuel Patricio García, whose historic treatises document his father’s method. A prolific composer, García’s works were applauded in Madrid, Naples, Paris, London, New York, and Mexico City. Un avvertimento ai gelosi (A Warning to Those Who Are Jealous) was designed to prepare García’s students for demanding operatic careers. Based on a comic farsa, this delightful opera displays the composer’s highly florid vocal style in brilliant arias and ensembles. The edition presents the score and libretto (with translation) and also provides detailed performance notes derived from García’s teaching method, including improvised ornamentation.