Library of Congress Subject Cataloging Manual: Subject Headings--Music Sections

I've just finished reading through most of the Library of Congress' Subject Cataloging Manual: Subject Headings for the creation of subject headings in music. Admittedly, this was not the most riveting of documents, and it took me three weeks to get through the music sections. I now understand the basics of assigning subject headings.

The primary concern is to provide at least one subject heading that represents the predominant topic of a work. Thus, the first subject heading should be as specific as possible in describing the work. Additional subject headings may be added to increase access. In MARC, there is a way to distinguish primary and secondary descriptors in a {650} field in the first indicator. However, both Ralph and Suzanne Mudge have told me that they do not ever use this indicator with subject headings. It makes me wonder, then, whether it really is all that important to make sure that the first subject heading represent the predominant topic of a work, because OPACs and ILSs search subject fields indiscriminately. I guess the lesson to take from this is the importance of creating subject headings that are as specific as possible.

I also learned about assigning free-floating subdivisions appropriately, such as "Arranged", "Excerpts", geographic, chronological, topical, and form subdivisions. These subdivisions have certain rules for use, and must be ordered appropriately. These rules are detailed in H 1160 of the Manual.

In regard to use of the "Facsimiles" subdivision, I read (and have had experience cataloging actual facsimile scores for this internship) that this subdivision is not applied to the primary subject heading, but in two added subject headings. The first is a generic heading for Music with free-floating subdivisions "Manuscripts" and "Facsimiles", in that order. The second is a subject heading for the composer, with the same two subdivisions added after the name. The example in H 1595 of the Manual looks like this:

650 #0 $a Organ music.
650 #0 $a Music $v Manuscripts $v Facsimiles.
650 #0 $a Bach, Johann Sebastian, $d 1685-1750 $v Manuscripts $v Facsimiles.

Finally, H 1917.5 descrbes music form/genre headings for medium of performance. There are complex rules governing the listing of instruments/voices for which a particular work was composed or arranged. This is complicated by use of genre designations that imply standard ensembles (a symphony is typically played by an orchestra, etc.), creating a number of situations where medium of performance is prohibited. With the huge variety of instruments, instrument families, and virtually endless possibilities for combining instruments and voices in new compositions, the rules quickly become complicated, and many exceptions must be noted. In the end, however, it isn't rocket science, and with some diligence one can read through the rules as needed in real-world cataloging.