What it is
The Graduale Romanum is the Church’s book of Mass propersGlossaryThe variable prayers and chants of the Mass or Office assigned to a given day—introit, collect, readings, and the like. in Gregorian chant: introits, graduals, tracts, alleluias, offertories, communions. Solesmes editions are the common reference for melody and assignment.
What it is not
Not the MissalGlossaryThe liturgical book containing the texts of the Mass—the priest's altar missal, or a hand missal for the faithful to follow. (which holds the prayers of the MassGlossaryThe Church's central act of worship—the Sacrifice of Calvary made present, and the sacrament of Christ's Body and Blood.) and not the BreviaryGlossaryThe Church's daily liturgy of psalms, hymns, and readings sanctifying the hours—also called the Liturgy of the Hours. (Office). Choristers reach for the Graduale; the priest reaches for the Missal.
How you encounter it
When a schola sings Qui habitat from the Graduale for the First Sunday of LentGlossaryThe forty-day penitential season before Easter—fasting, prayer, and almsgiving in preparation for the Passion and Resurrection. — or any Sunday proper from that book.
