Abstract: In this paper,①a brief introduction is given to the history of research on multilayer feedforward neural networks;②a systematic review is given to some important achievements in the field of multilayer feedforward networks;③some existing problems and tendencies in the study of multilayer feedforward networks are pointed out,and a few of feasible methods for solving those questions are suggested;④a systematic analysis of approximation mechanism of feedforward networks with a scale,limited discrete point set ...