Watch the BBC documentary “N is a Number” portraying Paul Erdős.

In case you don’t know, Erdős was a hardcore mathematician in the sense that he lived for mathematics and performed mathematics 24/7. Every mathematician knows him and there’s even the Erdős number that states how many papers you are “away” from him.

There is a really good book about him by Bruce Schechter (MY BRAIN IS OPEN: The Mathematical Journeys of Paul Erdos).