The Liber Brevior was created in response to the need of parish choirs for a book that would include the ordinary sung portions of the Mass (Kyrie, Credo, Sanctus, Agnus Dei) as well as the daily changing parts (the propers), but not the Divine Office, which is not generally sung in parishes. Hence, in 1954, the Liber Brevoir was published by the Desclée publishing house in Belgium and the Gregorian Institute of America in America. This is a complete reprinting of that 1954 Edition.