The Arabian Peninsula is known in Arabic as jazírat al-‘árab , literally “the island of the Arabs.” It has the shape of a rectangle spanning 1,200 by 900 miles at its extreme measurements. Its territory occupies a little over one million square miles. The Peninsula is separated from the neighboring world by natural barriers: water on three sides (Persian Gulf, Arabian Sea, Indian Ocean, and Red Sea) and the Syrian Desert on the fourth. The land consists of barren deserts, mountains and plateaus (especially in the west), and steppes. The Peninsula’s southernmost part is affected by the Indian Ocean’s monsoons that bring in a limited amount of rainfall. This area and the mountainous areas of North Yemen receive enough rainfall to allow local populations to grow wheat, millet, sorghum, and palm trees. The sandy desert, called al-Rub‘ al-Khali (the “Empty Place”), in the southeast and the Nufud desert in the north have almost no water (see Figure 1.1).