Considered the most significant French poet and composer of the fourteenth century, Guillaume de Machaut composed a body of work unrivaled in volume and influence among his contemporaries; his music enjoyed performances for decades after his death, and his poetry influenced writers well into the fifteenth century, including such luminaries as Geoffrey Chaucer. This new, multivolume series of Machaut’s complete works uses one of the most authoritative medieval sources for his compositions: Paris, Bibliothèque nationale de France, fonds français 1584. Unique in the series for its exclusive emphasis on music, Volume 9 presents Machaut’s twenty-three motets, representing the largest surviving collection by a single composer and about a quarter of all surviving fourteenth-century examples of this polyphonic musical genre. Intended for performers and scholars alike, this edition presents clear, readable scores alongside detailed commentaries, full English translations of French and Latin texts, variants for each piece, and up-to-date bibliographies.