The objective of this study is to assess the growing role of Special Forces in modern warfare, with specific reference to the United States of America. The main question that the study seeks to address is what are the implications of the growing role of Special Forces in modern warfare and on the traditional conventional-unconventional debate. This monograph seeks to look at the growing role of the Special Forces and Special Mission Units, specifically those of the United States since the end of the Cold War up to and including the 2001 invasion of Afghanistan. As such the study will describe and analyze conventional and unconventional warfare and forces; the roles and missions of Special Forces and the composition of the US Special Forces and Special Mission Units; the role of US Special Forces in modern warfare prior to the September 11, 2001 terrorist attacks; and the role of the US Special Forces in the 2001 invasion of Afghanistan. The study demonstrates that since the end of the Cold War in the 1990’s, unconventional warfare has increasingly become more ubiquitous and can be said to be replacing, or at least equalling in stature, conventional warfare.