The Lyndon Baines Johnson Library and Museum, constructed on the campus of the University of Texas at Austin, was completed in 1971 and dedicated on May 22, 1971. It was the nation's fifth presidential library and the first to be located on a university campus. There it serves as a center for scholarly research and as a historical museum. Scholarly interest in the LBJ Library centered on its unusually rich archives of manuscripts and audio-visual records. Photographic negatives, motion picture films, and sound recordings added to the dimensions of the archives. An extensive collection of political cartoons captured highlights of American government and politics since the 1930s. More than 30 million pages of manuscripts, mostly papers of President Johnson, formed the core of the research collection. As the most comprehensive single collection of materials on a president of the United States, it spanned Lyndon Johnson's entire political career. Added to the Johnson papers were those of Lady Bird Johnson and many of Johnson's contemporaries and associates. The library continues to gather these materials from historically minded individuals to preserve them for the nation's heritage. Operated by the National Archives and Records Administration, the LBJ Library is one of a system of presidential libraries devoted to objective research through preservation of materials related to those who have held the job of president of the United States. Chester A. Newland was named first director of the Johnson Library in October 1968. He was succeeded by Harry J. Middleton in 1970. Related to the establishment of the Lyndon Baines Johnson Library, but under the administration of the University of Texas at Austin, the Lyndon B. Johnson School of Public Affairs was opened in September 1970 under the directorship of John A. Gronouski, former postmaster general and United States ambassador to Poland. The school is located in Sid W. Richardson Hall, adjacent to the Johnson Library, on the campus of the University of Texas at Austin. The museum had two major exhibitions on American history per year. In the early 1990s the library and museum underwent a major renovation project. At that time the LBJ Library and Museum had more than 400,000 visitors per year. In 1995 the library housed 45 million pages of historical documents.