The Irrationality of √2

Why no fraction equals the diagonal of a unit square: the ancient proofs, the best approximations from Babylon to Pell, the digits, and the questions still open

The Irrationality of √2 — the unit square and its diagonal, the classical and picture proofs, the best fractions and Pell's equation, the Babylonian tablet YBC 7289, Heron's method, the spiral of Theodorus and a million digits of √2