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Library of Congress > LC Online Catalog > Frequently Asked Questions

Frequently Asked Questions about the LC Online Catalog

Accessing the LC Online Catalog

  1. When I try to access the LC Online Catalog, I get a message that "all available connections are in use?" What does that mean?
  2. Periodically a timeout dialog box appears on my screen. Can you give me more information on session timeouts?
  3. How do I access the LC Online Catalog through the Library's wireless connections?

Searching/Browsing the LC Online Catalog

  1. I'm sure the Library has the item I am searching for, but I can't find it in the LC Online Catalog. Does the Online Catalog list every item in the Library's collections?
  2. I've checked the LC catalogs mentioned above, and it still looks like the Library doesn't have what I need. Now what?
  3. Are there short URLs that I can use to bookmark the Browse, Advanced Search, and Keyword Search pages?
  4. Why can't I find Name and Subject authority records in the Online Catalog?
  5. What do the different numbers mean on an LC Online Catalog record? How do I search for these numbers?
  6. What LC Online Catalog support is available for Unicode? How does the Catalog handle punctuation and special characters?

Search Results and Output

  1. Where do I find the Library "Request in" location displayed on LC Online Catalog records? Can I put the item on reserve before I arrive? Does the Library allow patrons to borrow books?
  2. Where do I find out more about the Library's Reader Registration program?
  3. If I cannot come to the Library of Congress, how do I obtain copies of items I find in the LC Online Catalog?
  4. How do I see an electronic version of the title I found in the LC Online Catalog?
  5. How do I download MARC or MARCXML records from the LC Online Catalog?
  6. Copying records into my catalog from the MARC Tags record display fails? What are my options?
  7. How can I reformat MARC records I've downloaded from the LC Online Catalog?
  8. How does relevance ranking work in my search results? What searches return relevance-ranked results
  9. Why do some records have the legend "Library of Congress Holdings Information Not Available?"
  10. How can I find out whether the Library of Congress has a particular issue of a journal I need?
  11. When I look at a record or a newspaper, the record says the Library of Congress has a complete run. But when I try to request a particular year at the Library, I'm told that the Library doesn't have it. Why is that?
  12. What does the phrase [from old catalog] mean?

Other Library of Congress Catalogs

  1. Where can I search the Braille and Audio catalog?
  2. What other catalogs does the Library have?
  3. Where can I search the Copyright files?

 

Accessing the LC Online Catalog

  1. When I try to access the LC Online Catalog, I get a message that "all available connections are in use?" What does that mean?

    The LC Online Catalog receives millions of search requests each day -- and at peak times, all connections may be in use. We are aware how frustrating this is, and we are constantly monitoring the number of simultaneous users to ensure the maximum possible access. Should you encounter connection problems, here are some tips:

    • Peak usage is typically Tuesdays, Wednesdays, and Thursdays between 10am and 2pm (US Eastern Time). We suggest trying to search before or after those hours, or on Mondays, Fridays, and weekends (during off-peak hours).
    • Please be persistent and keep trying. Users are leaving the system and freeing up connections, at about the same rate that they are entering the system. Connections open up continually as users exit the system. If you continue to try several times in quick succession, you will move up in the queue and gain access more quickly.
    • An alternative text-based interface is available through the LC Online Catalog Z39.50 Gateway. More about the Z39.50/SRU protocol for information retrieval is available at the Z39.50 Maintenance Agency site.

  2. Periodically a timeout dialog box appears on my screen. Can you give me more information on session timeouts?

    Because the LC Online Catalog receives millions of search requests each day, we need to mimimize the number inactive sessions to make sure active searchers can access the Catalog. The Library, therefore, terminates your search session when you do not navigate from one page to the next at least once in five minutes.

    To keep your search session active, a timeout dialog box will appear two minutes before your session will expire, giving you the opportunity to refresh the counter. When your session closes, you will lose your search history.

  3. How do I access the LC Online Catalog through the Library's wireless connections?

    Onsite Library patrons with personal wireless-enabled devices may access the LC Online Catalog through the Library's free wireless service. Wireless users at the Library have access to research materials that may be limited to onsite use or have other restrictions on further dissemination because of copyright or licensing agreements. Restrictions on the use and further dissemination of these resources are the same whether researchers are accessing them using Library computers or via the Library’s WiFi connections.

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Searching/Browsing the LC Online Catalog

  1. I'm sure the Library has the item I am searching for, but I cannot find it in the LC Online Catalog. Does the Online Catalog list every item in the Library's collections?

    The Library of Congress acquires material from all over the world in many different formats, in hundreds of languages, and in diverse subject areas. Six methods of acquisition are used: purchase, Copyright deposit, exchange, donation, the Cataloging in Publication (CIP) and Preassigned Card Number (PCN) programs, and transfer between federal government agencies.

    While the Library of Congress is one of the largest libraries in the world, it does not have a copy of every item every published. The Library's permanent collections are shaped by Collection Policy Statements, with technical agricultural works acquired mainly by the National Library of Agriculture and clinical medical works by the National Library of Medicine. Note that not all items received by the Library are selected for retention in the permanent collections.

    In addition, many items from the Library's special collections are not represented by individual entries in the LC Online Catalog. These materials are instead described as aggregations. LC Online 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 accessible onsite (including items found in fee-based online services) are linked through the 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.

    For more information, see What other catalogs are available?

  2. I've checked the LC catalogs mentioned above, and it still looks like the Library doesn't have what I need. Now what?

    If you believe the Library doesn't have what you are looking for please contact a reference librarian through the Library's Ask a Librarian service.

    Also try your local public or college library. Most libraries have access to a number of online databases. They can also locate and borrow items for patrons through Interlibrary Loan. Your local library is often the fastest and easiest resource for finding hard-to-find items.

  3. Are there short URLs that I can use to bookmark the Browse, Advanced Search, and Keyword Search pages?

    Yes, you can use the following short URLs to bookmark the LC Online Catalog search pages:

  4. Why can't I find name and subject authority records in the LC Online Catalog?

    While references and scope notes from the Library’s name and subject authority records are integrated into LC Online Catalog Headings Browse Lists, full MARC 21 authority records cannot be directly searched or retrieved in the Catalog. To search authority records directly, please go to Library of Congress Authorities at http://authorities.loc.gov/. For more information, see About Library of Congress Authorities.

  5. What do the different numbers mean on an LC Online Catalog record? How do I search for these numbers?

    Records in the LC Online Catalog contain a confusing variety of numbers, including:

    Descriptions of numbers found in LC Online Catalog records and searching suggestions are available on the Searching Numbers and Index Search Codes help pages.

  6. What LC Online Catalog support is available for Unicode? How does the Catalog handle punctuation and special characters?

    The LC Online Catalog uses Unicode (external link) (UTF-8 encoding) for searching, displaying, printing, and downloading records. In 2004, all Catalog records were converted to the Unicode standard for MARC 21. In addition to Roman scripts, the Catalog contains records in the following languages/scripts: Chinese, Japanese, Korean; Cyrillic-based scripts; Greek; Hebrew, Yiddish; and Perso-Arabic script (e.g., Arabic, Persian, Pushto, Sindhi, Urdu). For more information, see Searching/Displaying Non-Roman Characters.

    In general, your preferred Web browser settings will not need to be changed to correctly view records that contain diacritics, special characters, or non-Roman characters. If you have problems, however, you may need to reconfigure your browser (external link).

    When searching the LC Online Catalog, most marks of punctuation in your query are converted to spaces. Some punctuation and diacritic marks are removed: apostrophes, alifs, ayns, middle dots, primes and double primes. A few special characters are retained in searches: ampersands (&), plus signs (+), at signs (@), number signs (#), and musical flat and natural signs (musical sharps are converted to spaces). Special characters are generally converted to their nearest alphabetic equivalent (for example, search an æ diagraph as "ae" or a þ thorn as "th").

    Bibliographic and holdings records can be downloaded in either MARC UTF-8 (Unicode) or MARC-8 (non-Unicode). The Library's Cataloging Distribution Service (CDS) also provides MARC 21 bibliographic and authority records in both MARC-8 and UTF-8.

    Emailed bibliographic and holdings records contain a brief display (Roman script), along with a persistent link to the full LC Online Catalog record.

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Search Results and Output

  1. Where do I find the Library "Request in" location displayed on LC Online Catalog records? Can I put the item on reserve before I arrive? Does the Library allow patrons to borrow books?

    Information about Library of Congress reading rooms and research centers is available on the Researchers site. This site links you to Library maps and floor plans as well as hours of operation.

    While retrieving material from the Library's over 500 miles of shelving may take approximately an hour, materials can be reserved ahead of time. In addition, serious and extended researchers can request one of a limited number of individual study shelves where charged materials can be held for long term use. Note: Items stored offsite may require additional time to be delivered to the Library campus.

  2. Where do I find out more about the Library's Reader Registration program?

    Public patrons of the Library's research areas are required to have a Reader Identification Card issued by the Library. These cards are free-of-charge and are valid for two years from the date of issue. Patrons must present in person a valid driver's license, state-issued identification card, or passport at the Reader Registration and Researcher Guidance Office, located in the Madison Building, Room LM 140 (First Floor, near the Independence Avenue entrance <view campus map>).

    Registered readers may request materials online through the LC Online Catalog using their individual account numbers. See the Guide for Requesting Materials in the Library's Online Catalog [PDF, 176KB] (revised August 2012) for additional information.

  3. If I cannot come to the Library of Congress, how do I obtain copies of items I find in the LC Online Catalog?

    The Library of Congress does not loan material to individuals, but some items may be loaned or digitized on a case-by-case basis. You should work through your local public or college library's Interlibrary Loan (ILL) program to initiate a request. Usually material is available at local and regional libraries; in some cases, local libraries charge a nominal fee for processing ILL requests.

    You may also purchase reproductions of some materials from the Library's Duplication Services. The Duplication Services site contain information on ordering, pricing, and Copyright clearance information.

  4. How do I see an electronic version of the title I found in the LC Online Catalog?

    While the LC Online Catalog does not link to electronic versions of every item in the Library of Congress collections, thousands of items in the Library's collections are available electronically, either through the Library or through freely-accessible web sites. LC Online Catalog records contain descriptive metadata, generally for "physical" items in the collections (books, periodicals, recordings, maps, images. music scores, etc.). Where possible, links to freely available full digital content are included in the records. In addition, databases, ejournals, and ebooks accessible onsite (including items found in fee-based online services) are linked through the E-Resources Online Catalog. Records for the Library's still images can be found in the Prints and Photographs Online Catalog.

    To help you identify electronic content in records, look for the label Links in Brief and Full Record displays. These links will take you either to the electronic item described by the record or to content associated with the item. In addition, electronic items may also be available by searching other Library catalogs.

  5. How do I download MARC records from the LC Online Catalog?

    Information on saving (download) MARC or MARCXML records in either the MARC UTF-8 or MARC-8 format is available at Print/Save/Email Help.

    Records containing LCCNs can be saved in MARCXML or MODS from individual record displays, using the LCCN Permalink service.

    In addition, records can be exported using Z39.50/SRU, either through the LC Online Catalog's Z39.50 Gateway or by configuring your Z39.50/SRU client according to the LC's technical guidelines. Z39.50/SRU exports can be formatted in MARC-8, MARC UTF-8, MARCXML, MODS, or Dublin Core.

    The LC Online Catalog does not support emailing records in MARC formats. Emailed record(s) are formatted as a short text citation that includes a hyperlink back to the LC Online Catalog record. For example:

           Persistent Link:  http://lccn.loc.gov/85043568
           Main title:  A Spanish renaissance songbook / edited by Charles Jacobs.
           Published/Created:  University Park : Pennsylvania State University Press, c1988.
           Description:  1 score (xi, 176 p.) : ill. ; 26 cm.
           ISBN:  0271004355 : $22.50

           CALL NUMBER:   M1623 .S74 1988 Copy 1
           Request in:  Performing Arts Reading Room (Madison, LM113)

  6. Copying records into my catalog from the MARC Tags record display fails? What are my options?

    Some catalog software enables you to import records into your catalog by copying the MARC Tags display of an LC Online Catalog record. If you experience problems when you copy a MARC Tags display, we recommend that you use the Tagged Display available in the Z39.50 Gateway. From the LC Online Catalog landing page, click on the link for the Z39.50 Gateway to the LC Online Catalog. The Gateway supports simple and advanced keyword searches as well as many of the left-match searches available in the LC Online Catalog. From your search results, click on the link More on this record, then select the Tagged display link. Because this MARC tagged display contains minimal HTML formatting, you should not experience copy and paste problems.

  7. How can I reformat MARC records I've downloaded from the LC Online Catalog?

    There are a number of third-party software products available specifically designed to manipulate and reformat MARC21 records, such as those from the Library's Catalog. In addition to a "card" display, most of these products also allow output in a variety of other bibliography and citation styles. A list of these products is available at: Open Directory Project (external link)

  8. How does relevance ranking work in my search results? What searches return relevance-ranked results?

    Results of Keyword Search and Advanced Search are arranged in a Titles List based on their relevance to your search. The most relevant items display first, as determined by three factors:

    • Uniqueness of search terms within the database
    • Proximity of search terms to each other within the record
    • Number of different search terms present in the record

  9. Why do some records have the legend "Library of Congress Holdings Information Not Available?"

    This legend displays on LC Online Catalog records for:

    • Items cataloged before they are published, through the Cataloging in Publication (CIP) program. Holdings information will be added when the Library receives the actual book.
    • Items that the Library is in the process of acquiring. Holdings information will be added when the Library receives the actual material.
    • Titles for which holdings and location information could not be created during migration from legacy systems to the LC Online Catalog. These records are being evaluated through long-term inventory projects.

  10. How can I find out whether the Library of Congress has a particular issue of a journal I need?

    Beginning October 1, 1999, Library staff check in new serial issues as they are received. Retrospective conversion of the older manual files will take several years. Until all titles have been converted, researchers should contact a reference librarian through the Library's Ask a Librarian service to find out whether a specific issue of a serial is held by the Library.

  11. When I look at a record for a newspaper, the record says the Library of Congress has a complete run. But when I try to request a particular year at the Library, I'm told that the Library doesn't have it. Why is that?

    Researchers commonly misinterpret the span of dates in records as holdings information. The Library has gradually been adding summary holdings for its newspapers. Eventually, researchers will be able to know from the LC Online Catalog what years of a newspaper the Library has in microfilm and bound formats.

  12. What does the phrase [from old catalog] mean?

    Library of Congress cataloging dates back to 1898. The LC Online Catalog includes many early records (primarily for books and periodicals) created by the Library between 1898 and 1980. These records -- originally maintained in a separate database -- are gradually being updated to reflect contemporary language and usage. Names and subjects found on older records often contain the legend "[from old catalog]" to indicate possible deviations from current LC practices.

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Other Library of Congress Catalogs

  1. Where can I search the Braille and Audio catalog?

    The Online Catalog of the National Service for the Blind and Physically Handicapped is available through both a standard interface and a special accessible text-based interface.

    Please consult the National Service for the Blind and Physically Handicapped site for additional information on NLS Book Catalogs and Listings.

  2. What other catalogs are available?

    In addition to the LC Online Catalog, the Library has multiple search systems for materials in its collections. Many of these are for special format materials, including digital collections such as: American Memory, the Performing Arts Encyclopedia, and the Prints and Photographs Online Catalog. For a more complete list, please see the Digital Collections and Programs web page.

    LC Online Catalog records for many Library of Congress archival collections are linked to more detailed guides searchable in the Finding Aids system. Records for portions of Library recordings can be searched in SONIC (Sound Online Inventory and Catalog).

    Databases, ejournals, and ebooks accessible onsite (including items found in fee-based online services) are linked through the E-Resources Online Catalog.

  3. Where can I search the Copyright files?

    Records of the U.S. Copyright Office (including registration information and recorded documents from 1978 to the present) are available through the Copyright Catalog.

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