tion of fields as a product of coordinate-dependent and time-dependent factors. The temporal variations of both media and fields are given by Fourier expansions. The successes of radiotechnique provided fertile ground for the dominance of sinusoidal waves in wave physics. This approach proved to be a powerful the­ oretical tool, since researchers were dealing with long trains of slowly varying quasi-monochromatic waves. However, the success of this concept and the stan­ dardizability of related designs engendered a peculiar psychological hypnosis of Fourier electromagnetics, which took over as a model for wave phenomena in such cross-discipIlnary areas of physics as optics and acoustics. Yet in providing a description of alternating fields, the presentation of such fields in terms of traveling waves with frequency wand wave number k is not a law of nature. One can see that such a presentation is not even a logical corollary of Maxwell's equations. What is more, this approach has become inadequate today for the analysis of fields excited by ultrashort transients in continuous media.