"Originally, this work has been prepared in the framework of a seminar of the University of Bonn in Germany, but it has been and will be extended (after being presented and published online under on 5/27/2005). First and foremost, to provide a comprehensive overview of the subject of neural networks and, second, just to acquire more and more A knowledge about LTEX . And who knows – maybe one day this summary will become a real preface!" Abstract of this work, end of 2005