Music Cataloging at Yale Call numbers

Class numbers in the Library of Congress Classification system are alpha-numeric. The letter portion includes one or more capital letters to indicate the general subject area. The number portion includes one or more arabic numbers to subdivide the subject area.

Class M, for music, is subdivided into three main sections:
M notated music (scores)
ML literature of music (books about music, such as biographies, histories, discographies, thematic indexes, etc.)
MT musical instruction and study (method books, studies and exercises intended for pedagogical use (as opposed for concert use), treatises, books on music theory, music-appreciation textbooks (even those with extensive musical examples), etc.; includes scores and books)

General guidelines for Class M (taken from http://www.loc.gov/catdir/cpso/LCC_M_GL.pdf)

Definitions of collection:
1. an item containing compositions by two or more composers,
2. an item containing works by one composer and selected from two or more of the composer's works,
or
3. an item containing one composer's works in more different forms or for a greater variety of performers than are provided for by any more specific class.

A collection is not to be confused with a set, which is a group of compositions published as a single work. This can be determined by an identifying number, such as an opus number or book number, etc., or a qualifying number that indicates the individuals parts are part of a larger work.

Further subclasses of collections are:
Miscellaneous collection: contains both original and arranged works
General collection: contains a greater variety of forms or types of works than may be provided for by any more specific neighboring class.
Special collection: contains two or more works by one or more composers that are of the type indicated for separate works, e.g., class collections of string quartets as well as individual string quartets in M452-M452.4.

type of collection or work	assign the five numbers in the span as follows:
Miscellaneous collections	1	2	3	4	5
Original compositions
Collections	2	3	4	5	6
Separate works	3	4	5	6	7
Arrangements
Collections	4	5	6	7	8
Separate works	5	6	7	8	9

For example, the span of numbers for viola and piano music is M224-M228. Using Table 2, the five numbers would be assigned beginning with the number
M224 for a collection of original and arranged works
M225 for a collection of original works
M226 for a single original work
M227 for a collection of arranged works
M228 for a single original work

The span of numbers for wind quintets is M555-M559, which is subarranged using Table 2:
M555 for a collection of original and arranged works
M556 for a collection of original works
M557 for a single original work for 5 woodwind and brass instruments
   M557.2 for a single original work for 5 woodwind instruments
   M557.4 for a single original work for 5 brass instruments
M558 for a collection of arranged works
M559 for a single original work

Note that the class number M557 is further subdivided: M557 is for quintets for a combination of both woodwind and brass instruments; M557.2 for woodwind quintets, and M557.4 for brass quintets. (Adding to the confusion is the terminology "woodwind quintet," which is used for quintets with flute, oboe, clarinet, horn, and bassoon. These qualify as "wind" quintets for cataloging purposes because they include a non-woodwind instrument; the horn is a brass instrument.) The rest of the span of numbers is not similarly subdivided. For example, M556 is used for collections of original works for either wind quintets, woodwind quintets, or brass quintets, not M556, M556.2, and M556.4. M559 is used for a single work arranged for either wind quintet, woodwind quintet, or brass quintet; M559.2 and M559.4 are not used.

Classifying works with keyboard:
Piano, etc.: "Unless specific classes are otherwise available, the term is meant to include harpsichord, clavichord, virginal, and similar keyboard instruments whose strings are plucked or struck."
Continuo: "Class works with continuo parts as if the continuo were played by one, not two, performers, and, in general, as if the chordal portion of the continuo part were for piano (harpsichord, etc.)"

Studies and exercises:
Pedagogical works (with or without accompaniment): class in MT studies and exercises
Concert works: class concert works titled "studies" by medium of performance in class M.

Class numbers for vocal music

Class numbers for vocal music tend to emphasis the accompaniment and are less easy to remember.

Secular and sacred works of the same type and for the same medium of performance are classed in different class numbers. For example, a secular song for voice and orchestra is classed in M1613 and a sacred song for voice and orchestra in M2103. There is no pattern like M1613/M2113 or M1619/M2119 in the class schedule, making it difficult to memorize the class numbers.

---

Some limitations of Class M are:

The schedule is inconsistent in the level of detail.

» Many classes are subdivided in detail. For example, the class numbers for music organ (M6-M14), piano (M20-M39), violin and piano (M217-M223), violoncello and piano (M229-M236), and orchestra (M1000/M1075) are further subdivided by type of composition (suite, sonata, symphony, etc.)

» Other class numbers are so general that a wide variety of works are classed in it. For example, see the class numbers M298 and 298.5 and M385, M485, M685, etc. and M386, M486, M586, etc. Most works that include percussion are classed in one of these class numbers, because percussion is not covered elsewhere in the schedule.

» Still other class numbers are in-between highly detailed and not detailed enough. For example, all music for two wind instruments, original or arranged, are classed in just two class numbers: M288 (collections) and M289 (separate works).

The entire schedule is oriented toward western art music.

It is difficult to use Class M to classify sound recordings. (Some libraries use a variation of LC Class M; other libraries shelve recordings by accession number or manufacturer number. One system used by many public libraries is the ANSCR classification system for sound recordings, which includes over fifty major categories into which sound recordings may be organized.)