Ask a child to draw a picture of a cactus, and the result will probably look like a saguaro. Indeed, mass media have made this denizen of the Sonoran Desert universally recognizable, and perhaps just as misunderstood. In Saguaro: The Desert Giant, Anna Humphreys and Susan Lowell share true stories about this amazing, anthropomorphic cactus that are at least as intriguing as the folklore. A saguaro can grow to be a towering fifty feet or more and live...