The core idea of this book emerged about a decade ago when I was working at the Hungarian Ministry of Defence (MoD). I worked extensively with the European Union (EU) and North Atlantic Treaty Organization (NATO) and was also involved in policy development regarding smaller multinational defence collaborations. At that time my impression was that the academic scholarship did not reflect my experiences and the everyday practices of European MoDs. While the academic debate primarily focused on the EU’s Common Security and Defence Policy (CSDP), the relevance of NATO was much bigger in defence, but most importantly, bi- and minilateral collaborations seemed to be even more relevant. I call them subregional collaborations in this book, while in this framework NATO and the EU are the regional, European-level multinational cooperative frameworks.

European militaries have established a plethora of subregional multinational defence collaborations, and although NATO- and EU-level processes have an impact on them, these smaller collaborations also influence Europeanlevel dynamics. My observation was that these smaller defence collaborations below the NATO and EU level provided the substance, the backbone, of military cooperation in Europe. Often the participating members of these subregional defence collaborations channelled their already existing practical cooperation into NATO and EU frameworks or rebranded them according to the newest vocabulary of these two organizations. The participating states of these subregional collaborations also coordinated their policies and intended to shape the debate in NATO and the EU. However, the dynamics behind starting a new defence cooperation in Europe was more complex than that, and I wanted to understand them in detail. Thus I started a PhD programme at King’s College London, and this book is a heavily revised and upgraded version of my PhD thesis.

As the reader will see throughout the book, my experience as a former defence official influenced my approach. Thus it will perhaps not be surprising that I propose that Defence Policy Communities (DPCs) should be the unit of analysis of multinational defence cooperation instead of governments or international organizations. The rationale behind this is that members of DPCs have the will and the opportunity to shape these collaborations. Of course, the DPC of every country is slightly different, but there are commonalities, and the staff of the MoDs and defence staffs, politicians and other government officials are usually the most influential members of them.