Does the online catalog list every item in the Library's collections?
I'm sure the Library must have the item I am searching for, but I cannot find it in the Library of Congress Online Catalog.
The Library of Congress acquires material from all over the world in many different formats, in hundreds of languages, and in diverse subject areas. Materials enter the Library from six primary sources: purchase,Copyright deposit, exchange, donation, the Cataloging in Publication(CIP) and Preassigned Card Number(PCN) programs, and transfer between federal government agencies.
Although the Library of Congress is the largest library in the world, it does not have a copy of every item ever published, nor does it retain copies of every item submitted through the acquisition sources listed above for its research collection. The Library's permanent collections are shaped by Collections Policy Statements, with technical agricultural works acquired mainly by the National Agricultural Library and clinical medical works by the National Library of Medicine.
In addition, many items from the Library's special collections are not represented by individual entries in the Library's Catalog. These materials are instead described in aggregated records. Catalog records for many archival collections are also linked to more detailed guides searchable in the Finding Aids system. Records for many of the Library's still images can be found in the Prints and Photographs Online Catalog, and portions of Library recordings can be searched in SONIC (Sound Online Inventory and Catalog).
Databases, ejournals, and ebooks (including items found in fee-based online services) are generally accessible onsite, in one of the Library's reading rooms, often through the Library's E-Resources Online Catalog. Records for works registered with the Copyright Office after 1978 are searchable in the Copyright Catalog. Card entries for some items cataloged before 1980 are only available to researchers onsite in the Library's Main Card Catalog.