The Rock Archives is part of Rabbi Joshua's personal library containing numerous books on the subject of the djinn and the world. In order to borrow a book from this library, Nimrod had to win a Pension Bet against Rabbi Joshua.
The Rock Archives themselves contain books by Joseph Rock, who expeditioned to the lands of Shamba-La. For its mysterious and hidden nature, many have traveled their in the past and have failed. These books were valuable and guarded by golems.