Often overshadowed by its more famous cousins (like pi and zero), the square root of 2 is nonetheless a very important number. While pi is the circumference of a unit circle, the square root of 2 is the diagonal of a unit square. What's more, the square root of 2 was the first known, and mathematically proven, irrational number.
In this dialog between a mentor and a young protege, the drama of how mathematical ideas are arrived at is opened up on every page. David Flannery has lectured on mathematics since 1975 at the Cork Institute of Technology, Ireland. He is co-author, with his teenage daughter Sarah, of the award-winning cryptography title In Code-A Mathematical Journey.
