Anyone can download and read Stephen Hawking’s 1966 doctoral thesis “Properties of expanding universes” now that the scientist has given permission for it to be open access.

Hawking is a theoretical physicist famous for his research in relativity and black holes. The 134-page dissertation, written when Hawking was only 24, is the most-requested item at the Cambridge library, according to the university. About 200 requests have been made for it since May 2016; the next most requested thesis was requested 13 times. People had to pay $85 for a digital copy of Hawking’s thesis, or physically go to the library, but now it’s free for download at the University of Cambridge's Open Access repository Apollo.

Since Cambridge made the thesis available to everyone, more than 60,000 people have accessed the work, which has caused the website to occasionally crash.

In a statement, Hawking said that he hoped the thesis would “inspire people around the world to look up at the stars and not down at their feet,” and added that everyone should have free access to all research.