The 21st century is now almost upon us and, whilst this represents a somewhat artificial boundary, it provides an opportunity for reflection upon the changes, and the accelerating pace of change, in our social, economic, and natural environments. These changes and their effects are profound, not least in terms of access to information and communication technologies, at once global in effect and manifest locally. These changes and their consequent demands are reflected in the theme of this volume: Synergy Matters, proceedings from the 6th UK Systems Society International Conference.