This book illuminates the basic concepts of quantum chemistry, and emphasizes atomic structure but not molecular applications. The author starts with a survey of the basic ideas and problems of wave/particle duality, the nature of wave function, and its statistical interpretation. He then discusses some important applications of Schrodinger's equation to chemically relevant situations, and probes the structure of the hydrogen atom, multiple-electron atoms and the periodic table of elements. The emphasis throughout is on the physical concepts and their concrete application.