[en] This paper reports on progress using cluster models to calculate electronic structure of oxide ceramics such as transition-metal monoxides, zirconia, α alumina, ruby, and copper-based superconducting oxides. The self-consistent field local density theory is used to find potentials, energy levels, and wave functions for a fragment consisting of N atoms embedded in the infinite solid. The single-particle spectra are compared with photoelectron and optical data, and with x-ray absorption and emission. Total energy calculations provide cohesive energies for prediction of relative stability of defect structures and lattice relaxation in the vicinity of impurities. A brief description is given of surface-structure calculations for an α alumina (0001) surface