  This review is devoted to precision physics of simple atoms. The atoms can
essentially be described in the framework of quantum electrodynamics (QED),
however, the energy levels are also affected by the effects of the strong
interaction due to the nuclear structure. We pay special attention to QED tests
based on studies of simple atoms and consider the influence of nuclear
structure on energy levels. Each calculation requires some values of relevant
fundamental constants. We discuss the accurate determination of the constants
such as the Rydberg constant, the fine structure constant and masses of
electron, proton and muon etc.
