This is an edition of, and commentary on, the Leofric Missal, a late-ninth- or early-tenth-century liturgical book combining sacramental, pontifical and ritual with cues for the sung parts of various masses, written by a possibly French or Lotharingian scribe. Subsequently, over the course of 130 or so years, the sacramentary-pontifical-ritual was considerably augmented, first most probably for the successors of Plegmund, archbishop of Canterbury (890 - 923), the man for whom it was probably originally compiled, then later at Exeter for Bishop Leofric (1050 - 72).