Abstract:The multiconfiguration relativistic random-phase approximation theory (MCRRPA) has recently been applied to a large variety of atomic systems of a multiconfiguration nature, and the agreements of the results with experiment are excellent for most cases. The formulation of the MCRRPA based on the time-dependent perturbation of a multiconfiguration reference state is reviewed. Its applications to photoexcitation and photoionization processes in atoms and ions are presented. Comparisons with other theories and with experiment are summarized. Merits of the MCRRPA in treatingdouble-electron excitations, core polarizations, and relativistic effects are demonstrated.