The authors discuss the application of the first-principles Korringa-Kohn-Rostoker coherent potential approximation to the calculation of the electronic structure of substitutionally disordered alloys with layer geometries (surfaces, interfaces etc)-the LKKRCPA. The canonical problem of this type is that of a single layer of a random binary alloy, and they present results for a Cu0.5Pd0.5 monolayer. They compare the effective scattering amplitudes and average densities of states with those of the bulk FCC alloy, and comment on the significance of the result for the surface electronic structure of Cu-Pd alloys. They outline how disordered layers may be embedded onto or between bulk substrates in order to treat real alloy surfaces or interfaces.