British Scientist Stephen Hawking has died at the age of 76.
A spokesman for his family confirmed the news on Wednesday.
He was one of the most respected - and well-known - scientists in modern history.
Hawking tried to explain some of the most complicated questions of life to the masses while working under the shadow of a likely premature death.
He was diagnosed with the wasting motor neuron disease at the age of 21 and was confined for most of his life in a wheelchair.
As his condition grew worse he had to resort to speaking through a voice synthesizer.
His book 'A Brief History of Time,' published in 1988, made him a household name across the world explaining complex and theoretical science to everyday people.
"Yet if as I hope, basic science becomes part of general awareness, what now appear as a paradox of quantum theory will seem as just common sense to our children's children."
Hawking was proud that the book contained only one math equation: relativity's famous E=MC squared.
In his 2013 memoir "My Brief History," Hawking revealed his disease led to the collapse of his two marriages.
But he also said it pushed him to work harder to explore the very limits of human understanding.
Both in the fields of astronomy, and the sub-molecular world of quantum theory, which Hawking said could predict what happens at the beginning of time- and its end.