It holds around 8 million items (including maps and sheet music) and, in contrast with the Bodleian or the British Library, many of its books are available on open shelves.
It is one of the six legal deposit libraries in the United Kingdom, and is therefore entitled to request a free copy of every book published in the UK and Ireland.
This group is a growing network, with a remit to "maximise efficiency while catering to the diverse range of user needs.
Many of the colleges also have special collections such as early printed books and manuscripts, and are often kept in a separate library.
For example, Trinity College's Wren Library holds more than 200,000 books printed before 1800, while the Parker Library at Corpus Christi College, has one of the greatest early medieval European manuscript collections in the world, with over 600 manuscripts.