In Granada, on a thirty-five-acre plateau atop a last spur of the Sierra Nevada, Spanish Islam erected its last royal palace, the Alhambra. For two and half centuries, twenty sultans of the royal house of Nasrid - named for Nasr, the grandfather of its founder - enjoyed this majestic residence, the last and best-preserved monument of a long-lived culture. Today, it remains a place of perfection, redolent of spiritual balance, not decay. The Alhambra reveals in its structures and decoration...