In 1938 Keyes D. Metcalf, Librarian of Harvard College and Director of the Harvard University Library (1937–1955), proposed a separate library building for rare books and manuscripts, based on the policy of decentralization of collections as a means of controlling the growth of Widener Library. In addition, Metcalf advocated the need for an air-conditioned building with controlled temperature and humidity for the preservation of materials. At that time the rare books were housed on the ground floor of Widener and part of the stacks adjacent to the rare book reading room, which was known as the Treasure Room (the area is currently by the Periodicals Reading Room).
Through the generosity of Arthur A. Houghton, Jr., Harvard Class of 1929, Harvard became the first American university to construct a separate research facility for the housing and study of rare books and manuscripts. The Boston architectural firm of Perry, Shaw, and Hepburn designed a classic neo-Georgian building, incorporating what was then state-of-the-art technology for climate control, air filtration, security, and the shelving of materials. The Houghton Library, dedicated and opened in 1942, won major architectural awards and became a model for other such research libraries.
In the early years of the Houghton Library the core of the collections consisted of the contents of the Treasure Room in Widener, the Harvard Theatre Collection, rarities and special materials transferred from the Widener stacks, and inaugural gifts of books and manuscripts by important Harvard benefactors, including Arthur Houghton and Philip Hofer, Harvard Class of 1921, founding Curator of the library's Department of Printing & Graphic Arts. An ambitious acquisitions program and major gifts combined to double the size of the library's collections within one decade, filling all available stack space in the Houghton building. When Lamont Library was planned in the late 1940s, Houghton was allocated one underground level of that building for its steadily growing collections. When Pusey Library was designed during the first half of the 1970s, substantial portions of secure space were devoted to Houghton's manuscript collections and to the vast and varied holdings of the Harvard Theatre Collection and its reading room, offices, and exhibition galleries.