Professor Kun Huang is widely known for his collaboration with Max Born in writing the classic monograph, ?Dynamical Theory of Crystal Lattices?. During his years of active research, he has made many important contributions to solid state physics. The present collection of papers is selected at his own choice as representing his most influential works. Thus one finds included his pioneering work on the interaction of radiation field with polar lattices and the resulting coupled vibration modes (later known as ?polariton?); the systematic development of his theory of radiative and nonradiative multiphonon transition processes associated with lattice relaxation; his early prediction of diffuse X-ray scattering due to crystal defects; and his recent research works on low-dimensional semiconductor structures, etc.Professor Huang has found by his experience that scientists interested in these papers often want to know more particulars underlying the research work (background, motivation and rationale involved etc.). Thus he was led to write a commentary which is published alongside the papers.