The field of artificial immune systems (AIS) is one of the most recent naturalcomputing approaches to emerge from engineering, computer science and theoreticalimmunology. The immune system is an adaptive system that employsmany parallel and complementary mechanisms to maintain homeostasis and defendthe organism against pathological agents. It is a distributed system, capableof constructing and maintaining a dynamical and structural identity, learning toidentify previously unseen invaders and remembering what it has learnt. Numerousimmune algorithms now exist, based on processes identified within thevertebrate immune system. These computational techniques have many potentialapplications, such as in distributed and adaptive control, machine learning, patternrecognition, fault and anomaly detection, computer security, optimization,and distributed system design.