Of the many physics issues involved in laser fusion, one of the least understood is the role of ionization and radiation in laser-heated plasmas. Ionization and excitation processes are important since they serve as an energy sink, as well as affecting the various transport coefficients. In addition, the radiative processes occurring in the plasma can not only act as a depletion mechanism for the energy but can also redistribute internal plasma energy from the deposition region to other plasma regions inaccessible via other phenomena. This presentation will be from the point of view of the modeler, whose job it is to make sense of the passive-radiative data obtained by the experimentalist as well as to explain the unobservable phenomena taking place via sophisticated computer models of atomic and radiation physics. Three areas will be discussed: (i) an introduction to the numerical modeling of ionization–radiation in laser plasmas, (ii) radiation diagnostics for laser fusion, and (iii) radiation energetics in laser plasmas.