A neutrino factory, used for short baseline physics, could provide unique and profound information about the internal structure of the nucleon. The unpolarized parton densities are already quite well known, thanks to a combination of neutral and charged current deep inelastic reactions over a wide range of Q². But with high intensities available from a neutrino factory it would no longer be necessary to utilize heavy nuclear targets, leading to a vast improvement in the precision of the data. However, the impact on our knowledge of the polarized parton densities would be much more dramatic. There the quality of the data is excellent, but because of the impossibility of utilizing polarized targets with present day neutrino beams, charged current data does not exist and the neutral current data only provide information about the combinations [Δq(x) + Δq̅(x)]. Thus nothing at all is known about the polarization of the valence quarks and the sea quarks separately! A truly dramatic improvement would follow from the construction of a neutrino factory.