Stephen Hawking was a brilliant theoretical physicist and is generally considered to have been one of the world’ s greatest thinkers. He held the position of Lucasian Professor of Mathematics at the University of Cambridge for thirty years and is the author of A Brief History of Time, which was an international bestseller. His other books for general readers include A Briefer History of Time, the essay collection Black Holes and Baby Universes, The Universe in a Nutshell, The Grand Design, and Black Holes: The BBC Reith Lectures, as well as the books in the George’ s Secret Key series. He died in 2018.