General staffs, the prime condition of military power, are sill, and more than ever, the brain of modern armies. In the aftermath of the first Gulf War, which has allowed a certain awareness to develop, the general staffs of the great countries of the Atlantic Alliance and of the European Union have undergone considerable transformations. The aim of these was to create previously inexistent interarmed structures, as well as being able to move from a geographic perception of security to a functional perception. Three levels of military action (strategic, operative and tactic) have thus been recognized, provoking a threefold division of European general staffs concerning the planning and conduct of military operations. During a coalition operation, the planning and conduct bodies possess an awesome complexity, not necessarily exclusively technical, and sometimes – if not often – hiding important strategic and political stakes among partners, as proved by the Operation Concordia in Macedonia or the Multinational Interoperability Council as well. – Summary AFRI-2005