By  Matin Durrani

A tiny, 83-page book about some of the basic principles of physics has been a surprise hit in Italy – becoming the single bestselling book of any kind to be published in the country this year.

The book has now been translated into English, entitled Seven Brief Lessons on Physics, and its author – the Italian-born theoretical physicist Carlo Rovelli – dropped by the Physics World offices in Bristol yesterday en route to giving a sold-out lecture about the book as part of the city’s Festival of Ideas.

In the interview above, Rovelli explains what the book’s about, how he managed to condense big physics ideas into such a short space – and why its success was absolutely not what he expected.

When he’s not writing popular-science books, Rovelli is based at the University of Marseilles in France, where he carries out research into loop quantum gravity, which he once tackled for Physics World.

If you want to find out more about the book, check out Penguin’s rather splendid interactive website.