HERA-3

A brief review is given on the physics potential of HERA beyond the presently approved programme. Questions of particular interest include QCD in a regime of weak coupling and high partonic densities achieved in eA collisions and spin physics with polarized colliding beams. Those two distinct programmes can be naturally merged and even substantiated by using polarized and unpolarized deuterons at the starting phase of the HERA-3 run. Basic machine implications and detector requirements are also discussed.