The lecture provides an introduction to the network description of living systems, first with the review of logic and basic mechanisms of a molecular free network for a particularly simple way of life, namely a virus that attacks bacteria.

It then provides a more general introduction to signal networks, the main point of which is to emphasize the usability of the network paradigm for characterization of complex systems.

The lecture will be illustrated with a series of dynamic simulations that can also be found as "Java applets" on the website www.cmol.nbi.dk