Abstract
This monograph shows power and elegance of algebraic methods in quantum mechanics for the exact and approximate solution of problems in atomic physics. It is shown that symmetries not only provide elegant solution of problems that can be solved exactly, they also substantially simplify the problems that has to be solved approximately.
Further, an elementary exposition of quantum electrodynamics (QED) and its application to low-energy physics is given. A thorough analysis of the role of relativistic, magnetic and QED effects in atomic spectroscopy is given.