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 important contributions to solid state physics. This collection of papers is selected at his own choice as representing his most influential works. Included is his 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 research works on low-dimensional semiconductor structures, and more. Professor Huang has found by his experience that scientists interested in these papers often want to know more particulars underlying the research work (such as background, motivation and rationale involved). Thus he was led to write a commentary which is published alongside the papers.