As demonstrated in this book, the form, shape and nature of transnational policing has been developing over several centuries, yet it remains poorly understood, both by academics and practitioners. There is little agreement around its nature and form or the extent to which it can be designed and realised. No theories have yet been developed which adequately capture the academic subject of transnational policing in order for it to be holistically shaped, refined and studied. Transnational policing as a concept represents only a disparate and disjointed assortment of structures, processes, relationships, networks and organisations, which shift and change over time, often with remarkable speed. The vast assemblage that is now addressed under the heading of transnational policing has become increasingly complex. New mechanisms and relationships have been established as older ones have died out, normally without an overarching ethos, strategy or sense of orderliness.