Here's a book on North American deserts that's as stark and startling as the subject itself, avoiding the macho stance of much nature writing while transmitting the small-scale miracles of Our grid ecosystems. Zwinger (Run, River, Run, 1975) keeps a tight reign on her authorial presence. Each of the 23 short chapters is titled after two desert inhabitants, and invokes an insight or experience that is intentionally less than a revelation, but more than a fact. In "Of Stork's-Bill and Red-Spotted Toads," for instance, Zwinger goes into the Mojave Desert's failed spa of Zzyzx, whose most famous inhabitants now are a colony of rare toads. In the span of a few short pages, we encounter the Indians, mountain men, land speculators, and Bureau of Land Management rangers who must monitor the endangered toads. Each paragraph is a description of a physical process--how lava erodes, why Joshua Trees grow to resemble human beings, the ability of toads to rehydrate through a pelvic patch--written as it seems to occur to Zwinger. She examines her reactions with the same equanimity when two rattlesnakes are discovered where she had been searching for toads a few hours before: "It never occurred to me that rattlesnakes might be cosseted in a cold, wet willow thicket in the middle of a chilly stream. Cave Crotalum." The four deserts presented here--the Chihuahuan, the Sonoran, the Mojave, and Nevada's Great Basin--have probably never been recorded in so compact and graceful a manner as this.