  We analyze the scenario of baryogenesis through leptogenesis induced by the
out-of-equilibrium decays of heavy Majorana neutrinos and pay special attention
to CP violation. Extending a recently proposed resummation formalism for
two-fermion mixing to decay amplitudes, we calculate the resonant phenomenon of
CP violation due to the mixing of two nearly degenerate heavy Majorana
neutrinos. Solving numerically the relevant Boltzmann equations, we find that
the isosinglet Majorana mass may range from 1 TeV up to the grand unification
scale, depending on the mechanism of CP violation and/or the flavour structure
of the neutrino mass matrix assumed. Finite temperature effects and possible
constraints from the electric dipole moment of electron and other low-energy
experiments are briefly discussed.
