Abstract
There are deep conceptual differences between the classical and quantum mechanical treatment of electromagnetic radiation processes. Nevertheless, it is possible to give a formally unified description of the spectral and angular distribution of radiation in both cases in terms of four-dimensional Fourier transforms of currents. We present parallel derivations of the basic radiation formulae utilizing classical electrodynamics as well as spinor quantum electrodynamics. In addition both derivations allow for the presence of a medium with an index of refraction. The practical application of these methods is illustrated by calculations of some specific radiation problems.