No one has had a greater influence on modern recreational running than writer Christopher McDougall. His 2009 book Born to Run introduced the masses to barefoot running and became a revolutionary bestseller. As a result, the multibillion-dollar running-shoe industry went through a dramatic upheaval, and today runners have a broad range of shoe types to consider, from minimalist slippers to ultra-cushy maximalist fatties. Now McDougall is back with a new book that chronicles his work training a sickly donkey to be an endurance athlete (no, seriously). Titled Running with Sherman, it tells the story of an unexpected journey that was really good for the donkey—but also for McDougall. Outside editor Christopher Keyes spoke with McDougall about this surprising turn of events and whether it means the rest of us should be running with animals, too.