(Lat.: ‘Book of common practice’).
The short title of a book first issued by the monks of Solesmes in 1896, Liber usualis missae et officii pro dominicis et festis duplicibus cum cantu gregoriano (‘Book of common practice for Mass and Office for Sundays and double feasts, with Gregorian chant’). It is a compendium, though not comprehensive, of prayers, lessons and chants for the more important services of the Roman Catholic Church as prescribed between the Council of Trent (1545–63) and the Second Vatican Council (1962–5). It includes the kyriale; Mass, Vespers and Compline for Sundays and feast days; Prime, Terce, Sext and None for Sundays and feasts of the First and Second Class; Matins for four festivals – Christmas, Easter, Pentecost and Corpus Christi; Lauds for feasts of the First Class; the liturgy for Holy Week; sundry litanies; and votive Masses.
The Liber usualis represents the culmination of a tendency, particularly noticeable in the Western Church, to combine in one volume for practical use selections from liturgical books hitherto kept separate; such combinations had earlier appeared in the Breviary, Missal and Anglican Book of Common Prayer. These multi-purpose, non-comprehensive volumes differ somewhat from early compendia such as those made for the master-general of the Dominican order, Humbert of Romans, in the 13th century (I-Rss XIV lit.1, GB-Lbl Add.23935), which contain the entire Dominican liturgy: these consist of entire books – the gradual, antiphoner etc. – bound together, rather than of conflated selections like the Liber usualis, and were used during visitations to check the accuracy of local books.
The Liber usualis is not an official Vatican liturgical book, but was nevertheless widely used before the Second Vatican Council. It was frequently reprinted and also appeared in editions with introduction and rubrics in English or French. Although the book became a standard teaching aid in university music departments and in seminaries, its usefulness as a source book for medieval chant is severely limited by the fact that it provides little information about the period and provenance of the chants it contains.
See also Liturgy and liturgical books §III.