Butler Library houses the 2 million volumes of Columbia University's general collection in the humanities and in the social sciences prior to 1974. It is the largest of the more than twenty libraries and collections comprising Columbia University Libraries. The building was financed by Standard Oil executive and philanthropist Edward S. Harkness and designed by James Gamble Rogers, opening in 1934 as "South Hall." It was renamed in 1946 in honor of Nicholas Murray Butler, president of the University from 1902-1945.
Although traditional in its Italian Renaissance design, the building was equipped with the latest library technology available at the time. The core of the library is the fifteen-tier steel-shelved stack, which was then the largest stack ever built as a single unit. The stacks (though not the reading rooms and offices) were air-conditioned; stack lighting was designed by George Ainsworth to approach the quality of natural light; there was an electric book lift, an electric book conveyor, and a lighted call board behind the main desk to inform students and researchers that books were ready to be checked out.