The Cult of Pythagoras shows how myths evolve in the history of mathematics. Some tales are partly true, others entirely false, but all show the power of invention in history. Pythagoras emerges as a symbol of the urge to conjecture: he has been credited with fundamental discoveries in math and the sciences, yet there is nearly no evidence that he really contributed anything to such fields at all. This book asks: how does history change when we subtract the many small exaggerations and interpolations that writers have added for over two thousand years?