Frequently Asked Questions: History, Humanities & Social Sciences

The Library of Congress holds an extensive collection of U.S. doctoral dissertations. Most of these dissertations do not have records in the Library of Congress's Online Catalog, however, and none are freely available online through the Library. Resources through which researchers can access the Library's collection of dissertations are discussed below.

The majority of the Library's dissertations are available on microfilm and have been acquired through a subscription with University Microfilms International (UMI), now known as UMI Dissertation Publishing (a division of ProQuest).  The Library's subscription was established in 1938, when UMI began microfilming dissertations for archival purposes. Although initially not all universities participated in this archival project by sending their dissertations to UMI for microfilming (the University of Chicago did not participate until 2009), today all major universities submit electronic dissertations to UMI; as a result, the program is very comprehensive.

Of the roughly 1,000,000 dissertation titles in the Library's collections, most are microfilm or microfiche and may be requested in person in the Library of Congress's Microform and Electronic Resources Center (Thomas Jefferson Building, LJ 139). Some early dissertations and those from the University of Chicago through June 2009 are found in paper copies throughout the Library's General Collections and can be searched by title or author in the Library's online catalog also available at catalog.loc.gov.

The Library of Congress also subscribes to ProQuest Dissertations & Theses Global (PQDT). This database provides citations for nearly five million dissertations from 1861 to the present, as well as the full-text of 2.6 million dissertations.  Full-text access to most dissertations since 1997 is available, along with full-text access to many pre-1997 dissertations. These dissertations can be downloaded in PDF format; other dissertations are available for purchase through the database. Due to the limitations of the Library's license to use this product, only researchers in one of the reading rooms at the Library of Congress are able to gain access to PQDT. The database is also available through many larger academic libraries. Of special note: dissertations in this database are indexed through Google Scholar. As noted by ProQuest: "An authenticated ProQuest dissertations user searching Google Scholar will be recognized by the ProQuest platform and connect to the full text in their library’s collection. Users who are not recognized are sent to a landing page where they can purchase the dissertation or access the first 24 pages at no charge. Dissertations that have been published using the ProQuest Open Access publishing model are available to all users for free."

If a dissertation is not available electronically through ProQuest Dissertations & Theses Global (PQDT) , the citation provides a unique number that can be used to request dissertations on microfilm, as specified above.

Several printed reference sources, also available at many academic libraries, offered cumulative coverage comparable to ProQuest Dissertations & Theses Global.  These are Dissertation Abstracts International; Masters Abstracts International; and American Doctoral Dissertations. The latter two print publications have ceased; and print editions of Dissertation Abstracts International no longer appear to be published.

For researchers who lack library access to PQDT, ProQuest offers various options for searching and purchasing copies of dissertations available through PQDT. Researchers who would like to purchase a known dissertation listed in PQDT but don't have access to the database can search for the dissertation by title, author, and order number, and then purchase a copy, through Dissertation Express.

An increasing number of free databases allow users to search for citations to and sometimes the full text of U.S. and international dissertations. For example:

• A limited version of dissertations submitted to ProQuest have been published as open access materials and can be searched through PQDT Open.
• The British Library's Electronic Theses Online Service (EThOS) allows users to search across 500,000+ theses from the United Kingdom for free and order their full text quickly and easily. Database content is also indexed in the larger EBSCO Open Dissertations database (see below).
• The Networked Digital Library of Theses and Dissertations contains nearly six million electronic theses and dissertations from the U.S. and other countries. Start your search here.
• Open Access Theses and Dissertations is an index of over 3.5 million electronic theses and dissertations (ETDs) from around the world. To the extent possible, the index is limited to records of graduate-level theses that are freely available online.
• The DART-Europe E-theses Portal includes more than 828,000 full-text theses and dissertations from 619 participating universities from 28 European countries.
• The Theses Canada Portal includes more than 200,000 electronic theses from the Library and Archives Canada's collection.
• EBSCO Open Dissertations includes records for more than 1.2 million electronic theses and dissertations, including the content of the former American Doctoral Dissertations database. By providing access to American Doctoral Dissertations, it offers a comprehensive record of dissertations accepted by American universities during 1933-1955 and listed in the print index Doctoral Dissertations. EBSCO Open Dissertations also indexes the content of the British Library's EThOS database (see above).
• Records for 800,000 dissertations from more than 90 countries and over 1,200 institutions are available through the Center for Research Libraries.
• Records for selected dissertations and theses by WorldCat member libraries can be found through the WorldCat database's Advanced Search page (limit search by Content to Thesis/dissertation).

The Networked Digital Library of Theses and Dissertations (NDLTD) lists additional online sources for international dissertations.

Many Library researchers are interested in accessing Masters theses. While many Masters theses are indexed by ProQuest, a comprehensive listing is not available through PQDT.  In addition, as a general rule the Library of Congress does not collect Masters theses. With few exceptions, the best source for obtaining Masters theses is the library of the university granting the degree.

Library of Congress researchers interested in Chinese dissertations can access the contents of Chinese Electronic Dissertations (CETD) database through the Airiti Library subscription database. Similarly, the China Doctor/Master Dissertations Full-text Database (1999- ) can be accessed through the larger China National Knowledge Infrastructure database. Researchers should contact the Library's Asian Reading Room for additional guidance locating dissertations in Chinese and other Asian languages. Additionally, researchers should:

• contact the Library's European Reading Room for additional guidance locating dissertations in European languages;
• contact the Library's African and Middle Eastern Reading Room for additional guidance locating dissertations in African and Middle Eastern languages; and
• contact the Library's Hispanic Reading Room for additional guidance locating dissertations in Spanish and other languages spoken in parts of the world encompassing the Caribbean, Latin America, and Iberia.