"Introduction to Atomic and Molecular Spectroscopy" discusses one electron system, Vector Representation of Momenta and Vector Coupling Approximations, Atomic spectra of hydrogen atom, Alkali metal atoms, Helium and two valence electron systems, X-ray spectroscopy, Hyperfine structure and isotope shifts, linewidths, effect of external fields on atoms, electron spin resonance, nuclear magnetic resonance, Mossbauer spectroscopy, rotational, vibrational and electronic spectra of diatomic molecules, Raman effect, basic concepts of lasers and its applications. Designed as a Textbook for Graduate, Postgraduate and research Students of Physics and Chemistry. It attempts to emphasize the physical basis of the subject without undue neglect of the mathematical aspects.