MARC Tags by Hundreds

The basic divisions of the MARC 21 bibliographic are:

In discussions of MARC 21 tags, the notation XX is often used to refer to a group of related tags. For example, 1XX refers to all of the tags in the 100s: 100, 110, 130, and so on.

0XX Control information, numbers, codes
1XX Main Entry (e.g. Author, etc.)
2XX Titles, etc.
3XX Physical description, etc. 
4XX Series statements
5XX Notes
6XX Subject added entries
7XX Added entries
8XX Series added entries
9XX Locally defined uses (NOTE: all Evergreen records have a 901 tag.  Do not delete this tag.)