Neutrino beams of unprecedented flux could be produced in a Neutrino Factory from muon decays. In the vicinity of the storage ring, short baseline experiments would perform a new class of precise tests of the theory and original deep-inelastic-scattering (DIS) studies. Thanks to the availability of high energy νe and νe, the long baseline experiments will be capable of very precise measurements of neutrino oscillations, including ability to solve parameter ambiguities and study of leptonic CP violation, for any value of the mixing angle θ13 above a fraction of a degree. Finally, the Neutrino Factory is the first step towards muon colliders.