The intense interest in Stephen Hawking's doctoral thesis has caused Cambridge University's website to crash.
Completed in 1966 when Hawking was 24, Properties of Expanding Universes explores ideas about the origins of the universe that have resonated through the scientist's career.
The university said the thesis was already the most-requested item in its online repository.
It was free to download on Monday to mark Open Access Week. The website was intermittently inaccessible during the day as it struggled to handle to the interest.
Hawking said he hoped making his thesis available to all would "inspire people around the world to look up at the stars and not down at their feet; to wonder about our place in the universe and to try and make sense of the cosmos".
