Duffing equation is one of the commonest examples to describe the resonance, harmonic vibration, subharmonic vibration,quasi-periodic vibration, almost periodic vibration, singular attractors and chaos phenomena, etc. And it has abroad applications in mechanics and electronic technologies.This thesis, which is divided into three parts, is concerned with the existence and uniqueness of the almost periodic solutions of nonlinear Duffing equations with damping.In the preface, the author simply introduces the h...