You know it from “land ethic,” but you’ll remember it for his incredible observations of nature. Aldo Leopold was a forester who spent his early career killing predators for the government, then changed his mind, and this book is the record of that turn. It came out in 1949, a year after he died fighting a grass fire on a neighbor’s farm. The first section is a month-by-month calendar of a worn-out Wisconsin sand farm he bought in 1935 and spent the rest of his life replanting, written from a shack that had been a chicken coop. The middle section collects sketches from forty years across the Southwest, the Midwest, and Mexico, including “Thinking Like a Mountain,” about watching the light go out of a wolf’s eyes and understanding what removing her would do to the range. The last section makes the argument the rest has been building toward: A landowner has ethical obligations to the soil, water, plants, and animals, not just property rights over them.