Travis Mills autographs a copy of his book "Tough As They Come" with his left prosthetic hand on Tuesday, Dec. 1, 2015, at a Barnes and Noble store in Augusta, Maine. Mills, 28, who was an Army staff sergeant when he lost all four limbs during an explosion in Afghanistan, aims to inspire others with his story. (Joe Phelan/The Kennebec Journal via AP), APTOPIX