Recently there has been a growing interest in the use of the biological immune system as a source of inspiration for solving complicated computational problems. The immune system involves many information-processing abilities including pattern recognition, learning, memory and inherent distributed parallel processing and for these, and other reasons, it has received a significant amount of interest as a metaphor within computing. This emerging field is known as Artificial Immune Systems (AIS), and applications of AIS include, machine learning, fault diagnosis, computer security, scheduling, virus detection and optimisation.