For centuries, horses have roamed Assateague, the narrow, ever-changing barrier island shared by Maryland and Virginia. The national seashore and state park established there in the 1960s saved them from a flood of resort development, but introduced controversy, conflict, and 2 million visitors a year. Can a herd that has endured tempest and hardship survive mass popularity or modern management? Bonnie U. Gruenberg has studied, photographed, and written about wild horses for more than 20 years. Distilled from her encyclopedic Wild Horse Dilemma (Quagga Press, 2015), each Hoofprints Guide...