From his post-war childhood in London through his undergraduate years at Oxford, Hawking was smart but (according to him) undistinguished. A great lover of jokes and bets, he made an art of doing as little work as possible. All that changed, however, when Hawking received a diagnosis of Lou Gehrig's disease, or ALS, at the age of 21, and began his transformation into the (still fun-loving) explorer and explainer of the universe that we know today....