It is upheavals which have occurred, since the end of the “cold war”, in the comprehension of the “security” category, that constitute the matter analyzed in the article. On considering conceptual and terminological aspects of modern theories of security, different Russian and foreign interpretations of the nature of international security, as well as operational models of a future system of international security, that experts bring forward, the author states the tendency taking root, towards multidimensional, complex understanding of the phenomenon in question — understanding that takes into account not only “tough” (warlike), but also “mild” (non-warlike) factors — economic, social, demographic, ecological, cultural, informational et al. The author regards as a manifestation of this tendency, the increasing popularity of the so-called cooperative security model which combines in itself, in his estimation, the best points of the collective and of the universal security conceptions.