Approved for public release, distribution is unlimited / The term "security" has always been vague in terms of its definition. After the end of the Cold War, however, this vagueness increased as new paradigms emerged. Those studying security need a better understanding of the term "security" to deal with complex issues within the broadly understood discipline of security studies. This thesis describes the uncertain nature of security by analyzing: (1) various definitions of security and some of the terms directly related to it in different contexts; and (2) the empirical meaning of security by examining threats as indicators of "insecurity," based on the different characters of threats, and levels of analysis from the field of international relations. The thesis argues that regardless of the vague meaning of the term "security," empirically its parameters are quite certain and definable by the specification of threats as indicators of insecurity. This clarification of the meaning of security studies, in turn, makes it easier for scholars and policy-makers to deal with this increasingly important sphere of human life. / Captain, Polish Army