Two-volume monograph (English physicists) on the principles of symmetry in physics . In t. 1 summarizes the theory of groups and the theory of representations of groups underlying the theory of symmetry, and considers the applications of this theory to the analysis of the structure of atoms and crystal lattices, as well as to the description of the symmetric properties of nuclei and elementary particles. In t. 2 deals with the electronic structure of molecules, the symmetry properties of space and time, permutation groups and unitary groups, the properties of particles in external fields. For a wide range of physicists and mathematicians - researchers, graduate students and students .