A Neutrino Factory based on a muon storage ring is the most powerful tool invented so far to study neutrino oscillations, having the best sensitivity and precision on the mixing angles θ23θ23 and θ13θ13 as well as on the CP violating phase δ. Parameter ambiguities can be solved in most cases thanks to the availability of a well understood flux of νeνe of high energy, allowing study of the golden and silver channels νe→νμνe→νμ and νe→ντνe→ντ respectively. Short baseline physics allows precision tests of the Standard Model and unprecedented DIS studies. The potent muon source should allow improved search for lepton flavour violation. Last but not least the Neutrino Factory is the first step towards muon colliders.