The 54m-long gallery is decorated with exotic wood shelving designed by Herrera, as well as a superb ceiling painted by Tibaldi. Philip II furnished the library with over 10 000 books, but many were lost in a fire in 1671 and during the Napoleonic wars. Today the library has over 40 000 books, displayed with the spine facing inwards, and some 2 700 manuscripts from the 5C-18C. The central display cases, standing on marble tables, contain various precious manuscripts, including an 11C Beatus.