The psalmody of the office of readings consists of three psalms or portions of psalms, each with its own antiphon. These are followed by two extended readings with their responsories, the first from the Bible (but not from the Gospels), and the second being patristic, hagiographical, or magisterial. As already mentioned, a Gospel reading may optionally be added, preceded by vigil canticles, in order to celebrate a vigil. These are given in an appendix of the book of the Liturgy of the Hours.