Composed by a 26-year-old John Knowles Paine between 1860 and 1866, the Mass in D, Op. 10 was the first large-scale American work performed before a sophisticated musical audience in a European capital. The premiere, with soli, 200-member chorus and orchestra, was conducted by the composer in Berlin's Singakademie on February 16th, 1867 to much acclaim. This newly engraved and thoroughly researched study score here has been prepared by Paine scholar David P. DeVenney from the composer's manuscript, an early fair-copy from ca.1868 and the 1866 first edition vocal score issued under the composer's supervision in New York.