From the current Preface: "I initially wrote this book with talented high-school students in mind, particularly those with math-olympiad type backgrounds. Some

From the current Preface: "I initially wrote this book with talented high-school students in mind, particularly those with math-olympiad type backgrounds. Some remnants of that cultural bias can still be felt throughout the book, particularly in assorted challenge problems which are taken from mathematical competitions. However, in general I think this would be a good reference for anyone with some amount of mathematical maturity and curiosity. Examples include but certainly not limited to: math undergraduate majors, physics/CS majors, math PhD students who want to hear a little bit about fields other than their own, high school students who like math but not math contests, and unusually intelligent kittens fluent in English."