Observable N-N-bar oscillation, high-scale see-saw and origin of matter

See-saw mechanism has been a dominant paradigm in the discussion of neutrino masses. We discuss how this idea can be tested via a baryon number violating process such as N-N-bar oscillation. Since the expected see-saw scale is high and the N-N-bar amplitude goes like M-5R, one might think that this process is not observable in realistic see-saw models for neutrino masses. In this talk I show that in supersymmetric models, the above conclusion is circumvented leading to an enhanced and observable rate for N-N-bar oscillation. I also discuss a new mechanism for baryogenesis in generic models for neutron-anti-neutron oscillation. (author)