QCD at high energy: perturbative, non perturbative and maybe perturbative

I will review the basic physics of strong interactions relevant to high energy scattering. I will concentrate on quantum evolution in QCD which predicts behavior of scattering cross section with increasing momentum transfer and energy, and will discus the qualitative differences between the two. Ideas about qualitatively new behavior at very high energies the so called perturbative saturation, or Color Glass Condensate will be introduced.