Book excerpt: Deserts, the Red Land, bracket the narrow strip of alluvial Black Land that borders the Nile. Networks of desert roads ascended to the high desert from the Nile Valley, providing access to the mineral wealth and Red Sea ports of the Eastern Desert, the oasis depressions and trade networks of the Western Desert. A historical perspective from the Predynastic through the Roman Periods highlights how developments in the Nile Valley altered the Egyptian administration and exploitation of the deserts. For the ancient Egyptians, the deserts were a living landscape, and at numerous points along the desert roads, the ancient Egyptians employed rock art and rock inscriptions to create and mark places. Such sites provide considerable evidence for the origin of writing in northeast Africa, the religious significance of the desert and expressions of personal piety, and the development of the early alphabet.