The physical problems concerned with the calculations of the radiative opacities of high temperature plasmas are presented, the emphasis being placed on such atomic processes as bound-bound transitions, bound-free transitions and the autoionization resonance broadening. Various broadening mechanisms related to the calculations of the bound-bound absorption are also discussed. The theories of the calculations of the radiative opacities of high temperature plasmas using detailed-term-accounting (DTA) approximation have been introduced. The theoretical results are compared with the experiments. Emphasis is placed on discussing some of the results we have obtained recently.