We evolve network topology of an asymmetrically connected threshold network by a simple local
rewiring rule: quiet nodes grow links, active nodes lose links. This leads to convergence of the
average connectivity of the network towards the critical value \(K_c = 2\) in the limit of large system
size \(N\). How this principle could generate self-organization in natural complex systems is discussed
for two examples: neural networks and regulatory networks in the genome.