Like the other monographs in the Combat Studies Institute's Global War on Terrorism Occasional Paper series, Public War, Private Fight? The United States and Private Military Companies provides another case study for use by modern military leaders to help them prepare themselves and their soldiers for operations in the current conflict. This work examines the widespread use of contractors by the military to help fill the massive and complex logistical requirements of a modern military force. Ms. Kidwell examines the use of Private Military Companies (PMC) as far back as the American Revolution and follows their evolution through the War with Mexico, the Civil War, the Spanish-American War, and the first Gulf War. She then analyzes the use of PMCs in Operation ENDURING FREEDOM and Operation IRAQI FREEDOM. Ms. Kidwell concludes that PMCs will be an increasingly important facet of US military operations for the foreseeable future; however, the use of contractors on the battlefield is not a panacea for all logistics problems. Logisticians, contractors, and military leaders who have responsibility for such operations in the current conflict against terror will gain useful insights to the advantages and disadvantages of these combat multipliers after reading this Occasional Paper. The United States has long utilized private military contractors to augment regular military forces in support of its national foreign policy and security needs. Commonly referred to as Private Military Companies (PMCs), contractors employ and manage civilian personnel from the private sector in areas of active military operations. Frequently, regular troops become dependent on the services contractors provide-a situation that may negatively impact military effectiveness. Since 1991, contractor support on and off the battlefield has become increasingly more visible, varied, and commonplace. Given the current manpower and resource limitations of the national military, the US will likely continue its extensive use of PMCs in support of military operations. This work addresses historical precedents and trends in American logistics, the current scope of contractor involvement in support of regular military forces, and the challenges posed as traditional military institutions integrate increasing numbers of civilian workers and privately owned assets into the battlespace. These problems increase the risk to US personnel and can induce budget overruns rather than savings, disrupt civil-military relations, and have detrimental consequences for the American economy and society. The work concludes by proposing a useful rubric to evaluate this "new" American way of war. This work considers PMCs and their interdependence with regular and reserve military units in a broad sense. It derives from unclassified material widely available; understandably, these sources limit the analysis. Lessons learned from the Operation IRAQI FREEDOM (OIF) and Operation ENDURING FREEDOM (OEF) theaters may alter findings. However, this study endeavors to frame the continuing dialog concerning the appropriate use of PMCs to support regular troops. It should stimulate further research and discussion by reviewing the history, theory, doctrine, and practice of employing private contractors on the battlefield. It is admittedly Armycentric; however, in a joint environment and with a common acquisition framework provided by joint doctrine, the generalizations garnered from this analysis will be relevant to other service branches.