The self-nonself theory Dishwasher Escutcheon Panel has dominated immunology since the 1950s.In the 1990s, Matzinger and her colleagues suggested a new, competing theory, called the danger theory.This theory has provoked mixed acclaim: enthusiasm and criticism.Here we assess the danger theory vis-à-vis recent experimental data on innate immunity, transplantation, cancers and tolerance to foreign entities, and try to elucidate more clearly whether danger Baby dolls is well defined.