ProQuest LLC is an Ann Arbor, Michigan-based electronic publisher and microfilm publisher. It provides archives of sources such as newspapers, periodicals, dissertations, and aggregated databases of many types. Its content is estimated at 125 billion digital pages. Content is accessed most commonly through library internet gateways, with navigation through such search platforms as ProQuest, CSA Illumina, Dialog, Datastar, Chadwyck-Healey, eLibrary and SIRS. Microfilm publishing is under the UMI brand. The current Chief Executive Officer is Kurt Sanford. ProQuest is part of Cambridge Information Group.
Eugene Power, a 1930 M.B.A. graduate of the University of Michigan, founded the company as University Microfilms in 1938, preserving works from the British Museum on microfilm. In his autobiography Edition of One, Power details the development of the company, including how University Microfilms assisted the OSS during World War II. This work mainly involved filming maps and European newspapers so they could be shipped back and forth overseas more cheaply and discreetly.
Power also noticed a niche market in dissertations publishing. Students were often forced to publish their own works in order to finish their doctoral degree. Dissertations could be published more cheaply as microfilm than as books. ProQuest still publishes so many dissertations that its Dissertations and Theses collection (formerly called Digital Dissertations) has been declared the official U.S. off-site repository of the Library of Congress.
As the dissertations market grew, the company expanded into filming newspapers and periodicals. The company's main newspaper database is ProQuest NewsStand.
Xerox owned the company for a time in the 1970s and 1980s, and it was later bought by Bell & Howell. The name of the company changed several times in this period, from University Microfilms to Xerox University Microfilms, to University Microfilms International, then shortened to UMI.
In the 1980s, UMI began producing CD-ROMs that stored databases of periodicals abstracts and indexes. At a time when modem connections were slow and expensive, it was more efficient to mail database CD-ROMs regularly to subscribing libraries, who installed the discs on dedicated PCs. The ProQuest brand name was first used for databases on CD-ROM. An online service called ProQuest Direct was launched in 1995; its name was later shortened to just ProQuest. The bibliographic databases are mainly sold to schools, universities and libraries.
In 1999, the company name changed to Bell & Howell Information and Learning, and then in 2001 to ProQuest Information and Learning.
In 1998 ProQuest announced the "Digital Vault Initiative", purported to include 5.5 billion images digitized from UMI microfilm, including some of the best existing copies of major newspapers dating back 100 to 150 years, and Early English books dating back to the 15th century. While work continues to digitize the contents of the microfilm vault, ProQuest is already providing navigation of 125 billion digital pages, including nearly 20 million pages of newspaper content dating from pre-Revolutionary War America.
In 1999 ProQuest acquired Chadwyck-Healey, a one-time microfilm publishing company that was one of the first to produce full-text CD-ROM databases. This acquisition gave Proquest ownership of a 100+ person publishing operation based in Cambridge, England and became the basis for a substantial overseas expansion.
In 2001 Proquest acquired Norman Ross Publishing, a small New York based microfilm publisher.
ProQuest Information and Learning acquired Seattle start-up Serials Solutions, a venture providing access management and search services for content hosted by other companies, in 2004.
In 2004 ProQuest Information and Learning acquired Copley Publishing Group.
ProQuest Company, then the parent company of ProQuest Information and Learning, sold it to Cambridge Information Group in 2006. ProQuest Information and Learning was merged with CSA in 2007 to form ProQuest CSA. Later that year it was renamed ProQuest LLC.
In 2010, ProQuest acquired two properties from LexisNexis, Congressional Information Service (CIS) and University Publications of America (UPA). CIS includes one of the world’s most exhaustive online collections of legislative content and highly respected statistical works, while UPA includes deep historical sets. The acquisition includes digital products and an expansive microfilm vault that will be energized through ProQuest’s strength in conversion from film to searchable electronic formats.
In 2011, ProQuest acquired Ebrary, an online digital library of full texts of over 170,000 scholarly eBooks. 
- Atlanta Daily World (1931–2003)
- Atlanta Journal-Constitution (1868–1939)
- Boston Globe (1872–1923)
- Chicago Defender (1910–1975)
- Chicago Tribune (1852–1984)
- Christian Science Monitor (1908–1994)
- The Globe and Mail (1844–2007)
- The Guardian (1821–2003) and The Observer (1791–2003)
- Hartford Courant (1764–1984)
- Irish Times (1859–2006)
- Los Angeles Sentinel (1934–2005)
- Los Angeles Times (1881–1984)
- Minneapolis Tribune (1867–1922)
- New York Amsterdam News (1922–1993)
- The New York Times (1851–2006)
- New York Tribune (1900–1910)
- Pittsburgh Courier (1911–2002)
- Toronto Star (1892–2007)
- The Wall Street Journal (1889–1990)
- Washington Post (1877–1986)
- ^ New CEO. ProQuest LLC. 2011.
- ^ Power, Eugene B.; Robert Anderson (1990). Edition of One: The Autobiography of Eugene B. Power. Ann Arbor, Michigan: University Microfilms. pp. 128–142. ISBN 0-8357-0898-5.
- ^ Library of Congress 1999 press release
- ^ ProQuest [brand]
- ^ ProQuest Information and Learning has acquired Copley Publishing Group, Inc., May 2004
- ^ "ProQuest acquires Dialog". ProQuest LLC. July 1, 2008. Retrieved on March 6, 2009.
- ^ "ProQuest signs agreement to acquire Dialog business from Thomson Reuters". Thomson Reuters. June 12, 2008. Retrieved on March 6, 2009.
- ^ "ProQuest Acquires Acclaimed Congressional Information Service and University Publications of America from LexisNexis". ProQuest LLC. November 30, 2010. Retrieved on December 7, 2010.
- ^ "". Retrieved on January 12, 2011.
- Eugene B. Power, Edition of One: The Autobiography of Eugene B. Power, Founder of University Microfilms, 1990 ISBN 0-8357-0898-5.
Wikimedia Foundation. 2010.