While CMAA is active in providing music for the Mass in English, we also remember the Second Vatican Council’s exhortation found in Sacrosanctum Concilium, the Constitution on the Sacred Liturgy:
Nevertheless steps should be taken so that the faithful may also be able to say or to sing together in Latin those parts of the Ordinary of the Mass which pertain to them. (SC 54)
The following chant editions should be part of any parish musician’s library.
The Kyriale contains the chant repertoire for ordinary parts of the Mass: the Kyrie, Gloria, Credo, Sanctus/Benedictus, and Agnus Dei, as well as the dialogue chants. This music is included in the books above, but when a separate book is useful, these editions are free to use and distribute.
The Graduale Simplex, prepared at the request of the Second Vatican Council, provides simple chants for the Ordinary Form Mass “for use in smaller churches”. In addition to settings of the Mass Ordinary, it provides seasonal chants to use in place of the propers.
The 1974 edition of the Graduale Romanum (published by Solesmes) is the reference collection for chant in the Ordinary Form.