This study was directed by the Commanding General, US Army Training and Doctrine Command, in the summer of 1999. NATO operations against Yugoslavia had just begun. Notwithstanding official announcements that ground forces would not be needed for the time being, expectations ran high that ground troops would ultimately have to be employed. The precise nature of the operations they would be called on to perform could not be foreseen, and consequently neither the size nor the precise character of the forces to be committed could be decided at the time. The range of possibilities was enough to give any commander or operational planner headaches: American ground forces could be engaged in direct combat within or beyond the province of Kosovo, then the focal point of NATO operations, against conventional forces or their surrogates. US troops could also be employed as an element of a peacekeeping operation confined to the province itself, or perhaps beyond, or any gradation of commitment between these extremes. No one with official responsibility could envision a scenario without ground troops of any sort. Only one assumption could be made with any sort of confidence: once ground forces were introduced, a significant part of their duties would be performed not in the open countryside but in areas that could to some degree be characterized as urban. Some such areas might be very small, no more than a village perhaps, with a population numbering in the tens. Some might be towns with only a few thousand inhabitants. Others might be much larger municipalities, with populations running to the tens of thousands. The question naturally arose: to what degree was the US Army prepared for this mission, ill-defined as it was at that particular time?