  Over the last decade, a new idea challenging the classical self-non-self
viewpoint has become popular amongst immunologists. It is called the Danger
Theory. In this conceptual paper, we look at this theory from the perspective
of Artificial Immune System practitioners. An overview of the Danger Theory is
presented with particular emphasis on analogies in the Artificial Immune
Systems world. A number of potential application areas are then used to provide
a framing for a critical assessment of the concept, and its relevance for
Artificial Immune Systems.
