The MARC (Machine-Readable Cataloging) format allows the capability of accessing library catalog records by any piece of information found in the catalog record. A library's MARC database is its most expensive investment in library automation, and the most crucial factor in the success of the library's automation. Intended for librarians or students new to MARC as well as more experienced MARC users, this book explains what MARC is and how it works, and offers a background on MARC database construction and management. This manual explains MARC records, interpreting many of the details that can be encountered in cataloging with or using MARC data. Import considerations and specifications for MARC database processing, MARC products, and online systems are discussed. This second edition provides updated information, and new information on MARC format integration and MARC format for community information. The book is divided into 13 chapters: (1) "MARC Theory and Development"; (2) "MARC Format Structure and Content Designation"; (3) "MARC Format Integration"; (4) "Patterns in the MARC Format"; (5) "Major MARC Bibliographic Codes"; (6) "MARC Records in Electronic Form"; (7) "MARC Database Processing"; (8) "MARC Database Products"; (9) "MARC-Based Online Systems"; (10) "MARC Authority Format"; (11) "MARC Format for Holdings Data"; (12) "MARC Format for Community Information"; and (13) "MARC Use in Different Types of Libraries." Includes a glossary and index. (SWC)