This is an annotated bibliography of books that may be useful to undergraduates in pure mathematics. I wrote the original version, with the help of some classmates, during my final year (1997-98) at the University of Chicago. To my great surprise, it has been useful to many people over the intervening years, and I am now maintaining it and accepting contributions on Github. I am not a "real mathematician", though some of the other contributors to this bibliography have since gone on to become such. I'm just some guy; I write software for a living, and try to learn small bits of math in my smaller bits of spare time. As you read, I ask that you forgive the arrogance and ignorance of a younger me, who knew everything, and take this resource as it was intended: as a guide that might help another student find their way.