Two topics are discussed in this thesis. The first is the calculation of cosmological baryon number generation in the early universe. These calculations are performed for a variety of SU(5) and SO(10) unified models. The effects of superheavy fermions and charge conjugation symmetry are discussed in the context of SO(10) models. The second section contains an analysis of natural fermion mass and mixing angle relations in a grand unified model based on SO(10). These relations are used to study neutrino masses and oscillations. Appreciable mixing is found only between μ and τ neutrinos. Spinor representations of the Lorentz group and of SO(10) are described in two appendices.
