In these lectures, I shall discuss small x physics and the consequences of the high gluon density which arises as x decreases. I argue that an understanding of this problem would lead to knowledge of the high energy asymptotics of hadronic processes. The high gluon density should allow a first principles computation of these asymptotics from QCD. This physics might be experimentally probed in heavy ion colliders or in high energy electron-nuclear collisions

PACS numbers: 12.38.--t, 12.38.Lg