Best-selling author Hiroshi Yuki has written over thirty books on mathematics, programming, and cryptography in Japan. His English-translated works includethe Math Girls and Math Girls Talk About... series. He lives in Tokyo. Tony Gonzalez has been translating academic, technical, and entertainment works since 1992. He holds a Master of Arts degree in mathematics education, and is a former mathematics and Japanese instructor. He lives in Atsugi, Japan.