The original description of Interleukin-1 as an "endogenous pyrogen" is now more than fifty year old. Still, Interleukin-1, the first named Interleukin, is experiencing a true renaissance and many recent studies have uncovered yet new pivotal roles of this cytokine family in the regulation of inflammation and tissue homeostasis. This Symposium is offering presentations on new emerging aspects of the Interleukin-1 family biology by extramural and intramural investigators, some of which have been among the pioneers of this field of research.