[Classweb-users] New edition of Class M

Paul G Weiss pwei at loc.gov
Thu May 10 12:50:06 EDT 2007

	As of Thursday, May 10, 2007 a new edition of class M of the
Library of Congress Classification has replaced the previous online
version in Classification Web.  The online version of LCC is the
official edition, and all LC catalogers of classified materials are
required to use it.  A print version of the schedule will also be
published in summer 2007, but printed schedules are now regarded as a
convenience for browsing, as they are never current.  The online
schedules are now updated overnight.

	A new outline of class M has also been prepared.  It is
available on the Cataloging & Acquisitions Web site at
http://www.loc.gov/catdir/cpso/lcco/lcco_m.pdf.  The new outline will
be included in the next cumulative print edition of LC Classification
Outline (expected publication date not yet set).

	The new edition of class M, which incorporates all changes made
to the 1998 edition through May 1, 2007, is virtually the same
structurally as the 1998 edition.  So there are no major changes in
where materials are classified, with one exception: geographic
subclasses, which occur many places in subclass ML, which formerly
provided poorly for certain regions and countries, notably Central and
South America.  Most of these sections have been reworked to provide the
same kind of arrangement given most of the other areas of the world,
first a class captioned General, and then a hierarchy, *By region or
country, A-Z.*  As a result, some classes where both general works and
works devoted to particular regions and countries have until now been
mixed together have, in the new edition, been overlaid with the
separation between general works and an alphabetized arrangement of the
rest, the standardized grouping.  There has also been a slight revision
of hierarchies in subclass ML for manuscripts and for works about sacred
music by denomination.

	Other features of the new edition are:

	*	Updated captions and better alignment of classes within
major hierarchies
	*	Many more notes under individual classification numbers
and spans of numbers explaining how they are to be used, and more
references between classes
	*	Inclusion of hundreds of classification numbers not
previously published.  These include geographic breakdowns for secular
vocal music and topics of songs in subclass M; types of dictionaries and
geographic breakdowns for literature about music in subclass ML; and
numbers for instructional techniques for instruments and specific
playing techniques in subclass MT
	*	All known obsolete class numbers are included, a
retrospective feature not previously provided in any schedule.  Some
obsolete numbers appear in the traditional way, as parenthesized numbers
in the schedule proper, but most are shown in a second range of tables
(labeled MZ) in which obsolete class numbers are grouped by major
hierarchy.  References to the tables of obsolete numbers are provided at
appropriate places in the schedule.  By incorporating obsolete numbers,
this edition of Class M is now effectively a cumulative history of this
schedule since its first publication in 1904.  As additional copies of
annotated older editions of class M are discovered and deposited in
CPSO, classification changes they record that have not yet been
incorporated online will continue to be added, so that the retrospective
aspect of the schedule can be further refined
	*	Information that formerly appeared in a separate
"Glossary and General Guidelines" section is now incorporated into the
	*	References to expansion tables (the first range of
tables, labeled M) are now provided next to the caption of every class
to which such a table applies.  The span of decimal subdivisions a
number occupies once the table is applied is now displayed as well.  As
a result, the problem of inadvertently assigning overlapping Cutter
numbers for adjacent classes should be eliminated
	*	Revised index incorporates more Library of Congress
Subject Headings (LCSH) vocabulary

	Users of LCC have had access to the front matter of the printed
editions in Catalogers Desktop.  The new preface for class M has now
been incorporated into the Desktop.

Cataloging Policy and Support Office
Library of Congress

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