The book is, in the words of the author, "a work in oral history based on the recollections of Erdős, his collaborators and their spouses".

[2] Hoffman received an assignment by The Atlantic Monthly in 1987 to profile Erdős, which won the National Magazine Award for feature writing.

A large part of the book concerns Erdős, but a lot of it is about other mathematicians, past and present, including Ronald Graham, Carl Friedrich Gauss, Srinivasa Ramanujan, and G.H.

The book overall portrays Erdős in a favorable light, pointing out his many endearing qualities, like his childlike simplicity, his generosity and altruistic nature, and his kindness and gentleness towards children.

However, it also attempts to illustrate his helplessness in doing mundane tasks, the difficulties faced by those close to him because of his eccentricities, and his stubborn and frustrating behavior.