  After a brief discussion of baryon and lepton number nonconservation, we
review the status of thermal leptogenesis with GUT scale neutrino masses, as
well as low scale alternatives with keV neutrinos as dark matter and heavy
neutrino masses within the reach of the LHC. Recent progress towards a full
quantum mechnical description of leptogenesis is described with resonant
leptogenesis as an application. Finally, cosmological B-L breaking after
inflation is considered as origin of the hot early universe, generating
entropy, baryon asymmetry and dark matter.
