Newton and Liebniz are generally considered the twin independent inventors of calculus - and both are credited with giving mathematics its biggest push forward since the Greeks. But in their own lifetimes, the joint glory of calculus was not enough for either and each declared war against the other, openly and in secret. This long and bitter dispute has been swept under the carpet by historians - perhaps because it reveals these two giants in their worst light. The full story is told here in narrative form for the first time.