This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book takes somewhat different approach, looking at how security communities are brought into existence by the talk and practice of communities of professionals bound by certain ways of doing things. It examines how the professional practices of the police contribute to the adoption of non-violent democratic policing norms that are transforming the Western Balkans from a conflict zone towards regional integration and ultimately into a security community. The book examines the contribution of the Croatian police as a profession/epistemic community to the creation of a Western Balkan security community. It investigates how regional cooperation is understood, exercised, and learned by military professionals in Bosnia and Herzegovina. The book probes the practices of the Montenegrin police as part and parcel of security community practice in the Western Balkans.