Published two years apart, the work of musicologist Heinrich Husmann on the music of the Syriac Orthodox Church remains a unique contribution to the liturgical study of that tradition. The first volume of this set is a study of the melodies of the weekly breviaries, arranged by the canonical hours of the days of the week. These studies are according to the offices as sung by Mor Cyril (Qorillos) Jacob, then Metropolitan of Damascus. The second volume contains the vigils, recorded by Mor Jacob's brother, Malphono Asmar Khouri. The vigils, in eight modes, are dedicated to the Virgin Mary, the saints, penitence, and the departed.