William C. Borland started his adulthood hiking up all forty-six peaks of the Adirondack Mountains. Before long, the more adventurous individuals in his group began to hike the high points of Vermont, New Hampshire, and Maine. Then, they began talking about how to hike the 2,160-mile-long Georgia-to-Maine Appalachian Trail. After reading Seven Summits by Frank Wells and Dick Bass, who detailed how they climbed the highest mountain on each continent,...