Classical methods in DIS and nuclear scattering at small x

In hadrons and nuclei at very small x, parton distributions saturate at a scale Q_s(x). Since the occupation number is large, and $Q_s(x)>>{\mathrm{\Lambda }}_{QCD}$, classical weak coupling methods may be used to study this novel regime of non-linear classical fields in QCD. In these lectures, we apply these methods to compute structure functions in deeply inelastic scattering (DIS) and the energy density of gluons produced in high energy nuclear collisions.