At UCLA Library, there are at least three or four catalogs to search for books and other library materials, depending on how extensively you want to search. Think of these catalogs as concentric circles:
Smallest Circle: UCLA Library Catalog
The UCLA Library Catalog is everything held (i.e. bought, licensed, subscribed to, acquired as gifts) by the UCLA Library. These materials include books, journals, magazines, DVDs and videos, manuscripts, microfilm, databases, and some web resources. The UCLA Catalog also includes cataloged materials for some related UCLA collections, including the English Reading Room, the Chicano Studies Research Center Library and Special Collections, and the LGBT Center Library. To search the Film and Television Archive or the Ethnomusicology Archive holdings, click on the "Select Collections" tab while in the main catalog.
Larger Circle: Melvyl UC Catalog
The Melvyl Catalog is everything held by the ten University of California campus libraries, including UCLA. Also included are records from the California State Library and the Center for Research Libraries. UCLA students, staff, and faculty can also request interlibrary loan of materials from the Melvyl Catalog.
Largest Circle: WorldCat
OCLC's WorldCat has catalog records from libraries worldwide, particularly North America. Most materials in the UCLA Library Catalog and the University of California system's Melvyl Catalog should show up in WorldCat. For researchers in the Performing Arts, WorldCat can be a very useful place to locate popular press materials and other titles available in local public libraries.