Giant dipole resonance of atomic nuclei. Prediction, discovery, and research

Three quarters of a century ago, in his paper "Quadrupole and dipole $\gamma$-emission from nuclei" [Phys. USSR 8 331 (1944); Zh. Eksp. Teor. Fiz. 15 81 (1945)], A B Migdal introduced the concept of quantum collective excitation modes into nuclear physics, thereby predicting the phenomenon of giant dipole resonance (GDR). GDR research has had an enormous influence on the formation of modern concepts relating to the dynamics of nuclei. We briefly discuss Migdal's paper and trace the history of theoretical and experimental studies of GDR. New forms of GDR and analogues of GDR in nonnuclear microsystems are mentioned.