Stephen Hawking is a world-famous physicist, but few people outside his field know what he has done. To the public he is a figure of tragic dimensions - a brilliant scientist and author of the phenomenal best-seller A Brief History of Time, and yet confined to a wheelchair, unable to speak or write. Hawking has mastered the two great theories of 20th-century physics - Einstein's General Theory of Relativity and Quantum Mechanics - and has made breathtaking discoveris about where they break down or overlap, such as on the edge of a Black Hole or at the Big Bang origin of the Universe. Here is the perfect introduction to Hawking's work by the author, who was helped by several long discussions with Hawking in researching the book.