Composed in 1818 on commission from an unknown individual in Lisbon, Adina was left to languish some years until its premiere in 1826, with a single performance in that city remaining virtually the only one on record until the opera's revival in 1963. The present vocal score is based on the critical edition of the orchestral full score prepared by Fabrizio Della Seta and published by the Fondazione Rossini of Pesaro in collaboration with Casa Ricordi. This Edition reconstructs for the first time the structure of the autograph score, which reflects the collective contributions of at least five different hands: having composed only four entirely new numbers and repurposed another three from Sigismondo, Rossini relied upon collaborators and copyists for the remainder of the music. Della Seta's detailed examination of this fundamental document (housed at the Fondazione Rossini) together with an informed assessment of the secondary sources, including a complete manuscript copy (housed at the British Library in London), various manuscript vocal parts with Rossini's autograph interventions (housed in the Royal Conservatory of Brussels), and the first edition of the vocal score published by Ricordi between 1855 and 1859, additionally reveals how the libretto printed in Lisbon for that single historic performance in 1826 differed substantially from the narrative disposition of the autograph score, with ample cuts and modifications (among those the suppression of the Aria Alì and the addition of a Coro). While neither attributable to Rossini himself nor pertaining to his original conceptual design of the opera, this Coro, the music of which survives in the first vocal score, is included as an Appendix to the edition.