His book "A Brief History of Time" was written for those who are not specialist readers and have no prior knowledge of scientific theories. An estimated 10 million copies have been sold worldwide. It's been called "the least-read best-seller ever".
His death was announced on the 139th anniversary of the birth of Albert Einstein.
"His contribution is to engage the public in a way that maybe hasn't happened since Einstein", said prominent astronomer Wendy Freedman, former director of the Carnegie Observatories.
"My disabilities have not been a significant handicap in my field, which is theoretical physics", he said in Science Digest in 1984.
He explained that Hawking shined a light on an area of science that many people didn't know about. (Invitations were sent only after the party was over.) Along with many physicists, Hawking had mused about whether going forward and back in time was possible. But I think it would be a great mistake.
He was confined for most of his life to a wheelchair. For his 65th he participated in a zero-gravity jet airliner flight. "This is a pity because if they had I would have got a Nobel Prize".
Hawking, who was born 300 years to the day after Galileo died, was the Lucasian Professor of Mathematics at Cambridge University.
Aimed at a non-scientific audience it attempted to explain some fundamental principles of physics and answer some of the oldest questions of mankind; how, why and where the universe began, how it works and where it will end.
American astrophysicist Neil deGrasse Tyson tweeted his condolences, with a characteristically cosmological reference. "All we need to do is make sure we keep talking".
Hawking was also recognized for his successful research on black holes.
Despite no guests gracing his party, StephenHawking was still hopeful that perhaps in the future a time traveler might eventually come across his message and decide to show up, as Newsweek report.
In 1975, he bet physicist Kip Thorne a Penthouse subscription that an astronomical object known as Cygnus X-1 was not a black hole.
But still, the viewers couldn't quite believe what they had just heard. Both of those concepts are cornerstones of current black hole theory.
His work ranged from the origins of the universe itself, through the tantalising prospect of time travel to the mysteries of space's all-consuming black holes. Initially, he theorized about the "singularity" of the baby universe in thick but elegant mathematical equations comparing early time to wave functions.
Kaley Cuoco, who plays Penny on the comedy, wrote, "It was truly such an honor getting to work with the incredible Stephen Hawking". "It goes well beyond the wheelchair". "And then he became a big supporter of it".
"We have lost a truly attractive mind, an astonishing scientist and the funniest man I have ever had the pleasure to meet", Redmayne said.