At twenty-one he was diagnosed with ALS, a degenerative neuromuscular disease. Though the disease weakened his muscles and limited his ability to move and speak, it did nothing to limit his mind. He went on to do groundbreaking work in cosmology and theoretical physics for decades after being told he had only a few years to live. He brought his intimate understanding of the universe to the public in his 1988 bestseller, A Brief History of Time. Soon after, he added pop-culture icon to his accomplishments by playing himself on shows like Star Trek, The Simpsons, and The Big Bang Theory, and becoming an outspoken advocate for disability rights.
