Francisco Asenjo Barbieri (1823–94) is one of the best known figures in the history of Spanish music. He was a composer, musicologist, director, and bibliophile. The core music holdings of the National Library of Spain consist of Barbieri’s own library, which he bequeathed to the institution in his will. Barbieri’s bequest is one of the most important sources for the history of Spanish music. The national library also acquired, in 1999, Barbieri’s personal archive, which includes autographed scores. The relationship between Barbieri and the national library began with the ceremonial laying of the first stone for the building, for which he wrote, in 1866, a triumphal march. The zarzuela (Spanish comic operetta) Jugar con fuego (Playing with fire) premiered on October 6, 1851, in the Teatro del Circo in Madrid and had great success over the course of 17 evenings. From the time of its premiere until 1860, it was the zarzuela with most performances in Spain. The work set the standards for the genre and the beginning of the zarzuelagrande (a zarzuela with more than one act). A great number of adaptations were made of Jugar con fuego, as well as arrangements and transcriptions of the complete work or of its most popular sections, for piano or voice and piano, but also for guitar and even some for chamber ensembles. Presented here, from the same year, is the work in two formats: the full manuscript score, which includes a dedication, in Barbieri’s handwriting, to the duke of Osuna, and a Madrid edition for voice and piano of the 12th number of the zarzuela. This is the baritone aria and chorus: “Quien mé socorre!” Included with the 1851 edition is the libretto by Ventura de la Vega, playwright, literature teacher of Queen Isabella II, and director of the Madrid Conservatory. The transcription for voice and piano of Jugar con fuego was the object of a legal battle between Barbieri and one of the most important music editors of the time, Casimiro Martín, who published a copy of it without the author’s permission. Barbieri could not defend his rights because he had not registered the work in this format in the Intellectual Property Register.