In 1880, Dr. William Osler of McGill University in Montreal published an article in a medical journal entitled, "Heredity in Progressive Muscular Atrophy as Illustrated in the Farr Family of Vermont." In that article he reported on the case of a farmer from Sutton, Vermont named Erastus Farr, and told the story of Erastus's father, an uncle and an aunt, and four cousins, all of whom had died young of this disease of muscle wasting, now known as Familial Amyotrophic Lateral Sclerosis. In his well-researched book, Dan Swainbank tells the rest of the continuing story: of the family's losses over...