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About the Librarian

David S. Mao became Acting Librarian of Congress Oct. 1, 2015, upon the retirement of James H. Billington.

As Acting Librarian, Mao oversees the entire Library and its various service units to ensure the Library’s services to Congress and the American people are provided effectively.

Mao previously served as Deputy Librarian of Congress, appointed January 12, 2015. During his time as Deputy, Mao oversaw a strategic re-alignment of Library service units, the appointment of a new Chief Operating Officer and the hiring of a new Chief Information Officer.

Before being named Deputy Librarian, Mao was the 23rd Law Librarian of Congress, serving in that position since January 2012. As Law Librarian, Mao managed the operation and policy administration of the Law Library of Congress, which contains the world’s largest collection of legal materials and serves as the leading research center for foreign, comparative, and international law. Mao often described the position as part law librarian to Congress, part steward for the law collections, and part ambassador to the word’s legal and library communities.

During his tenure as Law Librarian, Mao expanded the Law Library’s collections, particularly in the area of rare law books; oversaw improvements to on-site law collection storage and renovation of the Law Library reading room; initiated new strategies to make U.S. public domain legal materials accessible online; and brought to the Library a 1215 Magna Carta for an historic exhibition on the eve of the Great Charter’s 800th anniversary.

Prior to becoming the Law Librarian of Congress, Mao served as the first Deputy Law Librarian of Congress, working as a key member of the Law Library’s leadership team. He managed the Law Library’s global legal research portfolio, including the Global Legal Research Center and the Global Legal Information Network. Prior to his appointment as Deputy Law Librarian, Mao was a section head at Congressional Research Service (CRS), Library of Congress.

Mao is a graduate of The George Washington University, where he majored in international affairs with a minor in Chinese language and literature. After earning his law degree from the Georgetown University Law Center, Mao was in private practice for several years before returning to graduate school to pursue a master’s degree in library science at The Catholic University of America. Before arriving at CRS in 2005, he held positions at the Georgetown University Law Library and within the research library of the international law firm of Covington and Burling LLP. He also was an adjunct professor at the University of Maryland–College Park.

Mao served a three-year term as the treasurer of the American Association of Law Libraries and was a member of its executive board. A member of the American Bar Association, he is admitted to the bar of the District of Columbia.