The concept of national security is essentially a modern one which has gained meaning and significance with the formation of nation-state. National security studies are also a more recent field pertinent to the 20th century. By the way, security should be regarded as an old and primordial category closely linked to human essence, and human beings looked at security as a ubiquitous friend even when they did not emerge as social beings. But with the lapse of time and change in human life and identity, the concept of security underwent a change. According to such presumptions, the main question of the writing is what developments have occurred in the security concept and what have been its parameters and characteristics in any historical period? This question can be answered according to the assumption of continuity or discontinuity in two historical or discursive ways. Taking advantage of mixed historical and discursive methods and assuming an evolutionary but interrupted change, the author argues that the security concept has passed four discursive changes according to specific historical periods and has experienced particular parameters and specifications. The main question of the writing is to address such an evolutionary (historical) change, while taking specific (discursive) parameters and traits of every period into consideration.
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