Preface (Med. Lat. prefatia, for classical praefatio, praefari, to speak beforehand), an introduction to a book,, also any preliminary or introductory statement. In liturgical use the term is applied to that portion of the Eucharistic service which immediately precedes the canon or central portion; the preface, which begins at the words Vere dignum, " It is very meet, right, &c.," is ushered in, in all liturgies, with the Sursum Corda, "Lift up your hearts," and ends with the Sanctus, "Holy, Holy, Holy, &c." In the Western liturgies proper prefaces are appointed for particular occasions (see Liturgy) .