The original Library was on the first floor of Old Quad (now staircase IV, room 4), at the western end of the north range. It was completed c.1520-1521, when the Bursar made payments for glazing, panelling and reading stands. Books were chained and could not be removed from the room, let alone the college. The Library was reserved for Fellows’ use until 1897. In 1556 a catalogue of books was prepared, which survives on a single sheet of parchment. Books which were kept in the Library included: John Foxe’s Book of Martyrs (Protestant history and martyrology), Henry Stephen’s Greek Lexicon, The Magdeburg Centuries (an ecclesiastical history), Works by Pliny (Roman author), Fagius (Renaissance scholar of biblical Hebrew) and Bellarmine (a Cardinal of the Catholic Church).
In 1648 Principal Samuel Radcliffe left money in his will to build the existing Chapel, Cloister and Library. Preparations for building the Library were started in November 1657, and the foundations were begun the following March. By the end of 1659 the Library was being glazed, and Bernard Rawlin received £14 12s for '504 foot of New square glass at 7d ye foot'. The books were put in place (chained) in 1664. The Library originally had open cloisters underneath to provide shelter from weather for those taking exercise. These Cloisters were used as the College's burial ground from 1669 to 1754 and there are fifty nine people buried there. In 1807 the Cloisters were turned into college rooms (probably by Sir John Soane). The Library and Cloisters abutt onto Old Quad and can be seen from Radcliffe Square.
In 1779 James Wyatt submitted refurbishment plans for the Library. The present ceiling was put up and the windows on the west side blocked to give more space for books. These remained blocked until 1955. The present bookcases at right angles to the wall were built in 1891, and heating and lighting were installed in 1897, in which year undergraduates were admitted to the Library for the first time.
In addition to the Main Library, Brasenose has two further libraries: the History Library and the Stallybrass Memorial Library. In 1950 a fire broke out between the Main Library and the Tower (which were undergraduate rooms). During the repairs the History Library was created on the top floor. The work revealed a fireplace with a wall painting above it (now hidden) and two Elizabethan chimneys. The Stallybrass Memorial Library, situated on New Quad and named after a former Principal, houses the College's law collections.