Each year, hundreds attempt to hike the 2,181 miles of the Appalachian Trail from Georgia to Maine. Those who perservere usually take at least four months. In 2011, long-distance hiker Jennifer Pharr Davis accomplished the feat in a month and a half: 46 days, 11 hours, and 20 minutes, to be exact. In so doing, she became the AT's overall speed record holder and the first woman to do so. Her book "Called Again" tells the very personal story of how her endurance and the love and support of her husband, Brew, helped her make history.