This ebook by Holk Cruse provides an introduction to the simulation of dynamic systems in biology based on the combination of system theory, biological cybernetics, and the theory of neural networks. Mainly written as text book for students of biology, it is based on illustration rather than mathematical expressions. The third edition has been improved by a rearrangement and minor expansion of the sections referring to recurrent networks. These changes allow for an easy comprehension of the essential aspects of this important domain that has received growing attention during the last years.