This chapter presents a straightforward narrative account, to the extent that one is possible, of the history of the Multinational Force from its violent beginning to the bitter end. The creation and establishment of multinational peacekeeping forces were intimately related to the series of events. The Israeli invasion of Lebanon entered a new and more dangerous. The agreement between the United States (US) and Lebanon took the form of an exchange of letters between the US Ambassador to Lebanon and the Deputy Prime Minister and Foreign Minister of Lebanon. In agreeing to the participation of US marines in the peacekeeping force in Lebanon, the Reagan administration tried to cover itself politically both at home and abroad. Negotiations between Israel and Lebanon were opened, under some American pressure, at Khalde on 28 December 1982. The international border with Lebanon and Syria is the last and most important line of defence where Israel has constructed a comprehensive surveillance and security system.