The M scheme is for music scores exclusively.
In Sibley, the vast majority of music scores are located on the
entrance floor of the library (2nd floor).
Exceptions to these are the scores M1-M5, and the folio (i.e. oversized) scores. The table below will explain the classification ranges, with their locations within the library.
MUSIC IN SETS AND SERIES
| Number | Description | Location |
| M2-2.9 | Historical, geographical, and other collections of music | 4th floor, down right walkway, across 1st row of horizontal stacks and up left walkway |
| M3 | Collected works of individual composers | 4th floor, horizontal stacks |
INSTRUMENTAL MUSIC -- ON 2nd FLOOR (For Folios, see below)
(
| Number | Description |
| M6-19 | Organ music |
| M20-39 | Piano music |
| M40-175 | Solo instruments without accompaniment |
| M200-298.5 | Duets |
| M300-386 | Trios |
| M400-486 | Quartets |
| M500-586 | Quintets |
| M600-686 | Sextets |
| M700-786 | Septets |
| M800-886 | Octets |
| M900-986 | Nonets and larger combinations of chamber music |
| M1000-1075 | Orchestra (Symphonies: M1001; Concertos: M1010-1037.4) |
| M1375-1380 | Instrumental music for children |
VOCAL MUSIC-- ON 2nd FLOOR (for Folios, see below)
| Number | Description |
| M1500-1618 | Operas and musicals (Vocal scores: M1503) |
| M1530-1610 | Secular choruses |
| M1611-1624.8 | Secular songs for one voice (Art songs: M1620-1621.4) |
| M1627-1853 | National music, folk songs, popular songs |
| M1990-1998 | Children's songs (M1998 scores are on the 4th floor) |
| M1999-2036 | Sacred choruses (including Masses, Oratorios, Cantatas) |
| M2102-2114.8 | Sacred songs for one voice |
| M2115-2146 | Hymnals |
FOLIO SCORES (OVERSIZE)
| Number (see above for classification details) | Location |
| M1-1002 | 3rd floor last row of stacks by south stairway |
| M1003-1499 | 3rd floor, final rows of stacks to wall |
| M1500-1528 | 2nd floor, last full row of stacks |
| M1529-2147 | 2nd floor, south wall |