Leader

Field definition and scope:

The Leader is the first field of a bibliographic record. It is fixed in length at 24 character positions (00-23). The Leader consists of data elements that contain numbers or coded values that provide information for the processing of the record.

Character positions 20-23 comprise the Entry map for the Directory. They contain four one-character numbers that specify the structure of the entries in the Directory. More detailed information about the structure of the Leader is contained in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media.

National-level and Minimal-level record requirements for the Leader and all 24 character positions are Mandatory.

The Leader is NOT repeatable.

Guidelines for applying content designators:

The Leader has no indicators or subfield codes. The data elements are positionally defined.

The table below includes all 24 character positions of the Leader in bibliographic records. Positions are conventionally numbered zero (0) through 23. For information on a specific character position and its codes, select:

Position	Description	NLR	MLR	Repeatability
00-23	Leader	M	M	NR
Data elements:
00-04	Record length	M	M	NR
05	Record status	M	M	NR
06	Type of record	M	M	NR
07	Bibliographic level	M	M	NR
08	Type of control	M	M	NR
09	Character coding scheme	M	M	NR
10	Indicator count	M	M	NR
11	Subfield code count	M	M	NR
12-16	Base address of data	M	M	NR
17	Encoding level	M	M	NR
18	Descriptive cataloging form	M	M	NR
19	Multipart resource record level	M	M	NR
20-23	Entry map	M	M	NR

Input conventions:

System-generated elements

Dependencies

Capitalization

Content designator history:

/06 Type of record

/07 Bibliographic level

/08 Type of control

/17 Encoding level

/18 Descriptive cataloging form

/19 Multipart resource record level