Besides the fact that Hawking is brilliant, he is an amazing person for his perserverence against his disability from ALS. He says, "I am quite often asked: How do you feel about having ALS? The answer is, not a lot. I try to lead as normal a life as possible, and not think about my condition, or regret the things it prevents me from doing, which are not that many."
His web site says, "Hawking has worked on the basic laws which govern the universe. With Roger Penrose he showed that Einstein's General Theory of Relativity implied space and time would have a beginning in the Big Bang and an end in black holes. These results indicated it was necessary to unify General Relativity with Quantum Theory, the other great scientific development of the first half of the 20th Century. One consequence of such a unification that he discovered was that black holes should not be completely black, but should emit radiation and eventually evaporate and disappear. Another conjecture is that the universe has no edge or boundary in imaginary time. This would imply that the way the universe began was completely determined by the laws of science.
"His many publications include The Large Scale Structure of Spacetime with G F R Ellis, General Relativity: An Einstein Centenary Survey, with W Israel, and 300 Years of Gravity, with W Israel. Stephen Hawking has three popular books published; and his best seller A Brief History of Time."