Leader

Field definition and scope:

The Leader is the first field of an authority 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 record requirement for the Leader and all 24 character positions is 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 authority records. Positions are conventionally numbered zero (0) through 23. For information on a specific character position and its codes, select:

Position	Description	NLR	Repeatability
00-23	Leader	M	NR
Data elements:
00-04	Logical record length	M	NR
05	Record status	M	NR
06	Type of record	M	NR
07-08	Undefined	M	NR
09	Character coding scheme	M	NR
10	Indicator count	M	NR
11	Subfield code length	M	NR
12-16	Base address of data	M	NR
17	Encoding level	M	NR
18	Punctuation policy	M	NR
19	Undefined	M	NR
20-23	Entry map	M	NR

Input conventions:

System-generated elements

Capitalization

Content designator history:

/05 Record status

/17 Encoding level

/18 Punctuation policy