Twice declared extinct, North America’s most endangered mammal species, the black-footed ferret (BFF), is making a comeback thanks to an evolving conservation regimen at more than thirty reintroduction sites across the continent. Lawrence Lenhart lingers at one such site in his proverbial backyard, the Aubrey Valley in northern Arizona. He clocks hundreds of hours behind the wheel, rolling over ranch ruts as he shines a spotlight over dusky sage steppe in the hopes of catching a fleck of emerald eyeshine. The beguiling weasel at the center of this book is more than a charismatic minifauna;...