Introduction

The NLC edits and publishes National Bibliography, Union Catalogue, and Library Collection Catalogue. In 1929, the NLC became the host of National Bibliography Union Catalogue editing, and was working on more than 30 kinds of bibliographies, such as the National Bibliography of China, General Bibliography on the Period of the Republic of China and China's Rare Books Bibliography. The ledger catalogue system of Chinese books has been founded ever since. The NLC is in charge of the compilation of standards and specifications, such as Chinese Library Classification, Chinese Thesaurus, Chinese Bibliographical Cataloguing Rules, China Machine-Readable Catalogue, and so on, which provide supports for national library operation development. 

In 1990s, along with the proliferation of computer technology and the rapid development of the network environment, the NLC issued 50 Years (1949-1999) of Chinese Books Bibliography (CD). Founded in 1997, the National Online Library Cataloging Center organizes and manages the online union cataloguing and sharing bibliography resources. At present, the online library cataloging database is continuously extended. By combing with national bibliographic portal, it has become a comprehensive national bibliographic database with large scale, rich varieties, wide coverage, and diversified service products. In 2011, the National Online Library Cataloging Center began to provide free bibliographic data services to member libraries, which actively promoted information co-construction and resource sharing. 

In recent years, the NLC has been promoting information resources integration and revelation continuously, established Wenjin search system, enhanced resources discovery ability, and satisfied readers' one-stop retrieval demands for various resources. Readers can quickly access to their needed resources and enjoy the convenient services.