Afghanistan's history, internal political development, foreign relations, and very existence as an independent state have largely been determined by its geographic location at the crossroads of Central, West, and South Asia. In modern times, as well as in antiquity, vast armies of the world passed through Afghanistan, temporarily establishing local control and often dominating Iran and northern India. Islam has played a key role in the formation of Afghanistan as well. Although it was the scene of great empires and flourishing trade for over two millennia, Afghanistan did not become a truly independent nation until the twentieth century. In much of the twentieth century, Afghanistan remained neutral. It was not a participant in World War II, nor aligned with either power bloc in the Cold War. However, it was a beneficiary of the latter rivalry as both the Soviet Union and the U.S. vied for influence by building such infrastructure works as roads, airports, water and sewer systems, and hospitals. The U.S. State Department Central Classified Files are the definitive source of American diplomatic reporting on political, military, social, and economic developments throughout the world in the twentieth century. (OCLC)