Stephen Hawking knew what he wanted to do by the time he was eight years old. His parents lived in London where his father was researching medicine. He did not want to follow his father as his parents hoped. Mathematics was not available at University College, so he did physics instead. Stephen was interested in studying the universe.  When he was 21, however, he was told that he had ALS --an incurable nerve disease, which affects walking, speaking, breathing, swallowing, and many other things. The doctors predicted that he had only a few years to live, but he didn't die. Instead, as his physical condition became worse, Hawking became more well-known in scientific circles. Hawking himself said that his disease was a big reason why he focused his attention on what turned out to be his real strength: theoretical   research. "What the doctors said made me determine to get the most from life, and life was no longer boring for me," Hawking says today, speaking from his wheelchair through a computer. In 1988, Stephen Hawking published a book called A Brief History of Time. The book tries to explain many of Hawking's physical and mathematical ideas and calculations without using maths. The book became a best-seller. His later books are Black Holes and Baby Universes and Other Essays and most recently in 2001, The Universe in a Nutshell. Of the three, the first one was made into a film in 1991. Hawking says, "Nowadays, muscle power is out of date. What we need is mind power --and disabled people are as good at that as anyone else." According to Hawking, his disease   _  .
stopped him from making greater achievements stopped him from becoming more famous made him focus all of his attention on research caused him to lose hope of living