This volume concerns a music manuscript written at the end of the fifteenth century and associated with the Brethren of the Common Life at Zwolle. The manuscript is bound together with an incunable containing one of the most influential theological treatises of the Devotio moderna: the De spiritualibus ascensionibus of Gerard Zerbolt of Zutphen. The music manuscript contains 25 one-part hymns and two text excerpts on the Four Last Things (death, judgement, heaven, and hell), the core theme of the Brethren's penitential meditation. The book deals with the codicological construction of the book, the transmission, and the function of the songs in their context of the practice of pentitential meditation. The multidisciplinary study makes an important contribution to research on hymns in the late Middle Ages as well as on the music and spirituality of the Devotio moderna.