[5] Known to Oxford scholars as "Bodley" or "the Bod", it operates principally as a reference library and, in general, documents may not be removed from the reading rooms.

Since the 19th century, underground stores have been constructed, while the principal off-site storage area is located at South Marston on the edge of Swindon.

Ceremonies in which readers recite the declaration are still performed for those who wish to take them; these occur primarily at the start of the university's Michaelmas term.

The English text of the declaration is as follows: I hereby undertake not to remove from the Library, nor to mark, deface, or injure in any way, any volume, document or other object belonging to it or in its custody; not to bring into the Library, or kindle therein, any fire or flame, and not to smoke in the Library; and I promise to obey all rules of the Library.This is a translation of the traditional Latin oath (the original version of which did not forbid tobacco smoking, though libraries were then unheated because fires were so hazardous): Do fidem me nullum librum vel instrumentum aliamve quam rem ad bibliothecam pertinentem, vel ibi custodiae causa depositam, aut e bibliotheca sublaturum esse, aut foedaturum deformaturum aliove quo modo laesurum; item neque ignem nec flammam in bibliothecam inlaturum vel in ea accensurum, neque fumo nicotiano aliove quovis ibi usurum; item promitto me omnes leges ad bibliothecam Bodleianam attinentes semper observaturum esse.Whilst the Bodleian Library, in its current incarnation, has a continuous history dating back to 1602, its roots date back even further.

The first purpose-built library known to have existed in Oxford was founded in the 14th century under the will of Thomas Cobham, Bishop of Worcester (d. 1327).

This small collection of chained books was situated above the north side of the University Church of St Mary the Virgin on the High Street.

"[13] Bodley was a former fellow of Merton College, who had recently married a wealthy widow,[14] and the son of John Bodley (d. 15 Oct. 1591) a Protestant merchant who chose foreign exile rather than staying in England under the Roman Catholic government of Queen Mary, and was thereby involved in Rowland Hill's publication of the Geneva Bible.

[11] There were around 2,000 books in the library at this time, with an ornate Benefactor's Register displayed prominently, to encourage donations.

Early benefactors were motivated by the recent memory of the Reformation to donate books in the hopes that they would be kept safe.

[17] Bodley's collecting interests were varied; according to the library's historian Ian Philip, as early as June 1603 he was attempting to source manuscripts from Turkey, and it was during "the same year that the first Chinese book was acquired",[18] despite no-one at Oxford being able to understand them at that time.

The agreement with the Stationers' Company meant that the growth of stock was constant and there were also a number of large bequests and acquisitions for other reasons.

In 1975, it was handed over to the Bodleian Library, and now provides office and meeting space for senior members of staff.

[31] In 1909, the prime minister of Nepal, Chandra Shum Shere, donated a large collection of Sanskrit literature to the library.

[39] The Lamson tube system continued to be used by readers requesting manuscripts to be delivered to Duke Humfrey's Library until it was turned off in July 2009.

[47] In November 2015, its collections topped 12 million items with the acquisition of Shelley's "Poetical Essay on the Existing State of Things".

Thought lost from shortly after its publication in 1811 until a copy was rediscovered in a private collection in 2006, the Bodleian has digitised the 20-page pamphlet for online access.

Until fairly recently, personal photocopying of library material was not permitted, as there was concern that copying and excessive handling would result in damage.

[58][59] Bodley wanted his librarian to be "some one that is noted and known for a diligent Student, and in all his conversation to be trusty, active, and discreet, a graduate also and a Linguist, not encumbered with marriage, nor with a benefice of Cure",[60] although James was able to persuade Bodley to let him get married and to become Rector of St Aldate's Church, Oxford.

The Bodleian is one of the libraries consulted by Christine Greenaway (one of Bodley's librarians) in Colin Dexter's Inspector Morse novel The Wench Is Dead (1989).

[66] The denouement of Michael Innes's Operation Pax (1951) is set in an imaginary version of the underground bookstack, reached at night by sliding down the "Mendip cleft", a chute concealed in Radcliffe Square.

[68][69] Historian and novelist Deborah Harkness, set much of the early part of her 2011 novel, A Discovery of Witches, in the Bodleian, particularly the Selden End.

[74] It can be seen in the opening scene of The Golden Compass (2007), Brideshead Revisited (1981 TV serial), Wonka (2023), Another Country (1984), The Madness of King George III (1994), and the first two, as well as the fourth, Harry Potter films, in which the Divinity School doubles as the Hogwarts hospital wing and the room in which Professor McGonagall teaches the students to dance, as well as Duke Humfrey's Library as the Hogwarts library.