The bindings of Islamic books are generally made on a pasteboard core covered with tooled leather. The decoration—typically a central medallion surrounded by frame, braids, and banding—is stamped, tooled, gilded, and occasionally painted. The insides of the covers are finished in an ornate filigree technique of cut leather, gilt, and color inserts. Contained within are a double frontispiece and confronting miniature paintings signed by Mahmud al-Mudhahhib ("Mahmud the gilder"). This book, which deals with philosophical advice for rulers, was copied for the Sultan Abul'l-Ghazi Abd al'Aziz, the khan of Bukhara, in 1551. Located in Central Asia, Bukhara was an important trading center along the so-called Silk Road, the great trade corridor linking China with the Middle East. As Islam spread along the trade routes, it introduced new and sophisticated art forms to remote parts of Asia.