Stephen Hawking has died at the age of 76, his family has said.
The British physicist was known for his work with black holes and relativity, and wrote several popular science books including A Brief History of Time.
"We are deeply saddened that our beloved father passed away today," a family statement said.
At the age of 22 Stephen Hawking was given only a few years to live after being diagnosed with a rare form of motor neurone disease.
The illness left him wheelchair-bound and largely unable to speak except through a voice synthesiser.
In the statement his children, Lucy, Robert and Tim said: "He was a great scientist and an extraordinary man whose work and legacy will live on for many years."
Obituary: Stephen Hawking
They praised his "courage and persistence" and said his "brilliance and humour" inspired people across the world.
"He once said, 'It would not be much of a universe if it wasn't home to the people you love.' We will miss him forever."
Factfile: Stephen Hawking
Born 8 January 1942 in Oxford, England
Earned place at Oxford University to read natural science in 1959, before studying for his PhD at Cambridge
By 1963, was diagnosed with motor neurone disease and given two years to live
Outlined his theory that black holes emit "Hawking radiation" in 1974
Published his book A Brief History of Time in 1988, which has sold more than 10 million copies
His life story was the subject of the 2014 film The Theory of Everything, starring Eddie Redmayne
