Somewhat in the book The Man who Loved Only Numbers[1], it's a biography of Paul Erdos who was mostly homeless and spent his life travelling around other mathematicians' homes staying with them a few days at a time, and Ron Graham did a lot of looking after him and his life, pay, bureacracy, etc, so gets quite a few mentions.

[1] https://en.wikipedia.org/wiki/The_Man_Who_Loved_Only_Numbers