<P> In liturgical use the term preface is applied to that portion of the Eucharistic Prayer that immediately precedes the Canon or central portion of the Eucharist (Mass or Divine Liturgy). The preface, which begins at the words, "It is very mete and just, right and salutary" (or a variation thereof) is ushered in, in all liturgies, with the Sursum Corda, "Lift up your hearts", and ends with the Sanctus, "Holy, Holy, Holy, etc ." </P> <P> In the Western liturgies, proper prefaces are appointed for particular occasions . In the various Eastern liturgies there is great variation . Among those who follow the Rite of Constantinople the audible portion of the preface does not change, but the silent prayer said by the priest will differ depending upon whether it is the Liturgy of St. John Chrysostom or the Liturgy of St. Basil the Great . Among the Oriental Orthodox Churches the preface will take different forms, depending upon the liturgical rite and / or the particular feast day . </P>

What is the preface in the catholic mass