Introduction to the Theory of Atomic Spectra is a systematic presentation of the theory of atomic spectra based on the modern system of the theory of angular momentum. Many questions which are of interest from the point of view of using spectroscopic methods for investigating various physical phenomena, including continuous spectrum radiation, excitation of atoms, and spectral line broadening, are discussed. This volume consists of 11 chapters organized into three sections. After a summary of elementary information on atomic spectra, including the hydrogen spectrum and the spectra of multi-electron atoms, the reader is methodically introduced to angular momentum, systematics of the levels of multi-electron atoms, and hyperfine structure of spectral lines. Relativistic corrections are also given consideration, with particular reference to the use of the Dirac equation to determine the stationary states of an electron in an arbitrary electromagnetic field. In addition, the book explores the Stark effect and the Zeeman effect, the interaction between atoms and an electromagnetic field, and broadening of spectral lines. The final chapter is devoted to the problem of atomic excitation by collisions. This book is intended for advanced-course university students, postgraduate students and scientists working on spectroscopy and spectral analysis, and also in the field of theoretical physics.