The North Atlantic Treaty does not have records or offi cial minutes of the constituents’ interactions between 1948-1949 nor travaux préparatoires to refer to. There are no collective documents or a drafting history with documentary evidence. There is, however, a two-page paper with a series of agreed interpretations of the treaty made by the Ambassadors Committee. The agreement was reached on the meaning of certain phrases and articles, but was not considered formal or for publication, it constituted simply the understanding of the representatives participating in the discussions as to the interpretation of those phrases and articles.Other documents available are wires exchange between representatives and their capitals; the British and French representatives’ exchanges are available. This is not suffi cient. For this reason, it is imperative to reconstruct what is available. This also makes necessary to address the three general multilateral treaties, NATO SOFA and its Protocol of Paris and the Ottawa Agreement, accompanied by the ‘rules of the organization’, which together cover not only the institutional requirements of NATO, but also create three difference international organizations within NATO.This all show the complexity of NATO as an international organization, arcanus, which is reinforced by the lack of formal travaux to shed light on certain particularities of NATO. The historical account of the four rounds of negotiations, the description of NATO governing treaties particularities with respect to NATO’s institutionalization, and the analysis of the North Atlantic Treaty provisions under the light of the above and NATO’s practice may cover the gap left by the absence of travaux and help academics and practitioners in their endeavours to decipher NATO’s complexities.