In my youth I am aware of it,

And in old age

I shall walk quietly

The beautiful trail.

from a Navajo benedictory chant describing the desert

Cacti dominate the Sonoran Desert vegetation near Tucson, Arizona (photograph by Peter Kresan).

What Is a Desert?

Approximately one-third of the Earth’s land surface is desert, arid land with meager rainfall that supports only sparse vegetation and a limited population of people and animals. Deserts—stark, sometimes mysterious worlds—have been portrayed as fascinating environments of adventure and exploration from narratives such as that of Lawrence of Arabia to movies such as “Dune.” These arid regions are called deserts because they are dry. They may be hot, they may be cold. They may be regions of sand or vast areas of rocks and gravel peppered with occasional plants. But deserts are always dry.