Villani is a charismatic character who, contrary to the popular image of a mathematician, owes much of his success to collaboration with colleagues. *Birth of a Theorem* sets out the work necessary to develop his ideas into a full proof, and work is definitely the correct word. He details late nights and long days, emails exchanged on Christmas day, and the frantic development of ideas for conference deadlines.

Villani’s trajectory through academia is impressive, as is to be expected from a Field’s medal winner, and the insight into how much was down to chance meetings and hard work is fantastic. This was also the book that has encouraged me to return to my dream of undertaking a PhD, although not in pure mathematics as I might have expected aged 18.

My only complaint is that my LATEX was never that great, and now is beyond rusty, and I would have expected all the equations in this popular maths book to be displayed in conventional notation, rather than having to do the mental work of converting the TEX script and then understanding the equations, in a field which I don’t have much knowledge of. Somewhere where the editor should maybe have stepped in. But the translation (from French) is very good.

I’m also back to thinking about the Collatz Conjecture again, although even less likely to find a route to a solution than I was a decade ago.

This is not the sort of book I expect to find in my local public library, but am very glad I stumbled across it there.