Volumes I und II contain the chants of the Proprium Missae for the Catholic eucharistic celebration, each in with melodic restitution as published since 1996 in Beiträge zur Gregorianik (BzG).

Above and below the square notation which has been adopted from the Graduale Romanum 1908 (Editio Vaticana) there are the newly handwritten adiastematic graphic signs of the ms Laon 239 and mss from the St. Gall family. The Ordinary of the Mass as well as Cantus varii in ordine Missae occurrentes are included; furthermore indexes which indicate, among others, the critical apparatus in the BzG as well as the manuscripts used.