Pergolesi wrote his Mass in D major for an unknown occasion. The composition however is similar in quality and commitment to his other Mass in F major. Numerous manuscript copies all over Europe testify to the fortunate reception of the work in the eighteenth century. As was traditional in Naples, Pergolesi limited his composition to the “Kyrie” and “Gloria”. The festive character of the work is emphasized by the rich scoring for vocal soloists, five-part choir and a full orchestra of strings and winds. This edition, made with strict philological criteria, is based as its main source on a set of parts preserved partly in Naples, partly in Montecassino. These parts were made for aperformance conducted by the composer, who added various autograph annotations. Among the secondary sources are two period Neapolitan scores, today in Bologna and Dresden. The book includes a historical introduction (which traces the history of the genre in Naples and the relationship between the two Masses by Pergolesi) and the critical notes.