Stephen Hawking’s A Brief History of Time: How an unlikely book became a mainstream bestseller

Stephen Hawking has died at the age of 76. He leaves behind an incredible body of work, not least one of the greatest popular science books of all time.

Professor Hawking was one of the greatest scientists ever to live, and his work shone a light on the previously dark world of black holes. But a large part of his achievement was not just discovering new frontiers in science but telling people about those that had already been found.

And the most famous part of that work was his book A Brief History Of Time, which took on the apparently impossible text of condensing the history, past and present of our entire universe into a relatively slim volume. Now it is considered easily one of the most important and widely-read texts published in the 20th century – but it could just as easily have lingered in obscurity.

Nobody ever expected a book about the unimaginable details of how time and space were formed would ever sell. It was a book written to explain where the universe came from and where it was headed, and the incredible intricate and complex events that happen in between.

But it sold. And then it kept selling, and never stopped.

The book sold more than 10 million copies in 20 years, and was translated into more than 30 languages. It didn't leave the Sunday Times's bestseller list for five years.

Its brutal simplicity was inspired by a clear-eyed approach to making the book sell: as recognition of the importance of making the book accessible, Professor Hawking admits in its pages that the readership would half for each equation that he included.

So he included just the one: E = mc². He didn't even include his own equation, the one that he said he would like on his own gravestone, despite the fact the book would have been an incredible success with just a fraction of its readership.

It has, for obvious reasons, been repeatedly re-issued and re-packaged in new ways, including illustrated editions and audiobooks. The book can be bought on Amazon, where it is once again becoming the most popular book for sale on the site.

Over time, those new editions have reached new generations. And each of them has been left inspired, say scientists and communicators.

“He was a true genius who had a great admiration of and connection to the public," said Katherine Mathieson, chief executive of the British Science Association. "Most people, when he published ‘A Brief History of Time’, would have thought a book about physics would not sell.

"But Stephen knew people would want to read it – and it turned out they did. He simplified and explained, but without gimmicks. His assumption that people are curious about the universe and black holes was true. He inspired us all to wonder."

The book ends with its most famous quotation. It is one that has been used to demonstrate that Professor Hawking believes in God – but he has been very clear, in the years since, that he meant the reference metaphorically and that he was an atheist.

"However, if we discover a complete theory, it should in time be understandable by everyone, not just by a few scientists," Professor Hawking concludes. "Then we shall all, philosophers, scientists and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason – for then we should know the mind of God."

He later noted that despite the controversy, that final sentence turned out to be inspired. ""In the proof stage I nearly cut the last sentence in the book... Had I done so, the sales might have been halved," he wrote in his own biography, My Brief History.