Cataloging Biblical Materials
Definitions of Psalters, Evangeliaries, Liturgical Books
Both the Psalms and the Gospels, as Biblical books, were put to special use as liturgical books. All the books of the Bible were represented in the Liturgy, that is in public worship, but in the form of isolated fragments in prayers and readings. There are two special forms of these liturgical books. In both cases, the Biblical texts were arranged according to the needs of the liturgical calendar, not according to the order in which they appear in the Bible.
The current liturgy of the Catholic Church does not have the Psalter per se, rather these manuscripts were produced when the Psalter was a separate book.
Since the content is the same (though not the arrangement or function), there must be a way of distinguishing them bibliographically. There are two ways of distinguishing them from editions of the Biblical text: either as an edition of the liturgical book, or as a work of art (or as a reproduction of a work of art).