In audiocommunication Fourier's theorem is so extremely important and inescapable that neither purely mathematical/formal treatment nor purely qualitative treatment of this topic is sufficient. Thorough conceptual understanding of Fourier's theorem and of Fourier transformation with respect to the signals and systems of audiocommunication, including the peripheral auditory system, is indispensable. In the early 1980s I attempted to teach myself such a conceptual understanding. The result was the paper [68]. The insights achieved then had enormous concequences for the work of my research group in the years to follow. In particular, those insights provide the basis and origin of what I describe in the topics Fourier-t transformation, Causal Fourier transformation, Laplace transformation, and Peripheral-ear transduction. The contents of [68] is fairly comprehensively outlined in the abstract.