The subject of this book is cross-disciplinary. Sigmoid functions present a field of interest both for fundamental as well as application-driven research. We have tried to give the readers the flavour of both perspectives. From the perspective of fundamental science sigmoid functions are of special interest in abstract areas such as approximation theory and probability theory. More specifically, sigmoid function are an object of interest in Hausdorff approximations, fuzzy set theory, cumulative distribution functions, etc. From the perspective of applied mathematics and modelling sigmoid...