Naturalist Joe Huttoâ€™s latest adventures in wildlife observation take him to Wyomingâ€™s Wind River Mountains. Hutto is living in a tent at 12,000 feet, where blizzards occur in July and where human wants become irrelevant and human needs can become a matter of life and deathÂ—to study the Rocky Mountain bighorn sheep. The population of these rare alpine sheep is in decline. The lambs are dying in unprecedented numbers. Huttoâ€™s job is to find out why. For months at a time, he follows the bighorn herds, meets mountain lions and bears, weathers injury and storms, and beautifully observes the incredible splendor of the Rocky Mountains. Hutto has a deep connection to Wyoming, having managed a large cattle ranch in his past. He weaves Wyomingâ€™s history of the cowboy, mountain ecology, and the lives of the bighorn sheep into a beautiful flowing narrative. Ultimately, he discovers that the lambs are dying of a form of nutritional muscular dystrophy due to selenium deficiency, which is caused by acid rainÂ—a grim ecological disaster caused by human pollution. Here is a new twist on a cautionary tale, and a new voice, eloquently ex-pressing the urgency that we mend our ways.