To solve moduli problem, thermal inflation was introduced. But it also reduces baryon asymmetry. In a paper , they proposed a simple extension of the Minimal Supersymmetric Standard Model which gives rise to thermal inflation and baryogenesis in a natural and remarkably consistent way. In this dissertation, I consider the $\lambda_\phis$ = 0 special case of the previous model, which is the minimal way to incorporate a Peccei-Quinn symmetry. I show that this even simpler extension of the MSSM generates an even richer and more complex, but even more remarkably consistent, cosmology.