A Jedi library was a database containing information relating to the Jedi Order and its history. Jedi libraries were administered by Jedi librarians (such as Atris, and Jocasta Nu) and accessible only to members of the Jedi Order. Some were even restricted to members of having certain ranks, such as Dorak's library in the Jedi Enclave on Dantooine, which was reserved for Jedi Masters only.
Perhaps the greatest Jedi libraries in the history of the Order was Odan-Urr's Great Jedi Library on Ossus, which was founded around 5000 BBY and destroyed around 4000 BBY, the one on Exis Station and the Jedi Archives in the Jedi Temple on Coruscant, administered by Jocasta Nu around the time of the Clone Wars.