The thesis deals with the Iraq-Iran War throughout the period September 1980 to October 1983. It attempts to trace the causes of the war and examines various hypotheses regarding its outbreak: for example, that the war was a result of territorial differences and historical hostility; of oil prices and production and of the ambitions of President Saddam Hussein to take over the leadership of the region and to establish Iraq's hegemony over the Gulf. The study tries to examine other factors such as the domestic situation in Iraq and the Baghdad Government's fears that the winds of the Iranian Revolution would cross its frontiers and would mark the end of the secular Ba'thist regime in Iraq. The Iraqi Government believed that a pre-emptive war would foil this plan and would end the source of all threats in the region, namely the Ayatollah's regime. Despite the various groups which attempted political mediation, none succeeded in the face of Iranian rejections. The Iranian Shia Clergy were deeply influenced by their religious and idealogical beliefs and dictated the policy of the country and of the war accordingly. To accept mediation was to admit defeat: they had learned this from their own history. Nor did the Iranian Revolutionary Government ignore the importance of demographic factors, geography and the economy in the pursuit of its own war aims. These factors and the hostile relationship between Iraq and Syria were all decisive elements in Iran's calculations. The impact of this lengthy war has had and will continue to have significant consequences for the social and economic structures of both countries and the author is forced to conclude pessimistically that there is no foreseeable solution to the war.