Leptogenesis is a cosmological consequence of the seesaw mechanism and provides a link between the observed baryon asymmetry and neutrino masses. We show which information can be inferred from leptogenesis on neutrino masses and on those high energy seesaw parameters that represent a sort of `dark side' for conventional experiments. We also report on a new scenario of leptogenesis that opens new opportunities for leptogenesis to be tested.

PACS numbers: 14.60.Pq, 14.60.St, 98.80.Cq, 13.35.Hb