The Man Who Loved Only Numbers
by Paul Hoffman
1998

This is a wonderful book, but it also took me four tries over nearly a decade to get all the way through. It presents itself as a biography of the mathematician Paul Erdös (1913-1996). In reality, the book goes off on a lot of tangents, and there are a lot of natural breaks where it’s easy to set down. It talks about world history and about mathematics and is pretty obviously based on an oral history project. However many tangents it goes on, though, it does always return to Erdös.

Erdös, for those who don’t immediately recognize the name, is the zero point of Erdös numbers—where actors have degrees of Kevin Bacon, mathematicians have Erdös numbers, showing how close they are to having collaborated with Erdös.

Erdös is also one of the few mathematicians who made serious contributions to the field of mathematics after the age of 30, Mathematics generally being a young person’s field. Erdös remained a productive and innovative thinker until his death in his 80s. He was also a very peculiar man, thus a great focus for a biography.

He also seems like a good example of how there are people who are delightful to hear about and make the world a more wonderful place but I’m still glad I don’t have to deal with them personally. (Having read Surely You’re Joking, Mr. Feynman! several times and enjoyed it immensely, the physicist Richard Feynman is likely another of these individuals.) Among other things, Erdös spent most of his life couch surfing at his colleagues’ houses, demanding that they talk mathematics 18 hours a day. He made it work, though, and there was always someplace for him to stay.

Anyway, the problem with the book is that while it is excellent text about a fascinating character, it is also really dense, and not particularly well organized. In addition to Erdös himself, the book describes some of the more accessible and yet unusual mathematical proofs, the lives of various other mathematicians, and a good amount of political history–both that Erdös dealt with and that other mathematicians, both contemporary and historical, dealt with. The history and the mathematics are all related to Erdös’ life and experience, but it’s still a bit like reading multiple books, each of which requires a fair bit of concentration to properly appreciate. The book clearly shows its basis in oral history, and Hoffman doesn’t manage to give it any strong, overarching structure.

It is still well worth reading, but it does take effort.