The Yale University Library is the library system for Yale University. It has over 15 million volumes across more than 40 branch libraries located around Yale's campus. The library collection has moved several times throughout Yale's history as it outgrew previous buildings. In the early 20th century, the collection surpassed 1 million volumes, making it clear a new dedicated library building was needed. A $17 million donation was given for the construction of Sterling Library, which was completed in 1930 and remains the main library.