Carroll Quigley, American historian and professor at Georgetown University, died January 5, 1977, leaving behind a manuscript on weapons systems and political stability, upon which he had been working on for the preceding twelve years. Very few would ever see his final work, that is, until today. For the first time in over 30 years, this manuscript is now available to the public in its entirety, unabridged and original format. Professor Quigley's Weapons Systems and Political Stability carries further toward completion the uniquely anthropological holistic analysis of history, which is the theme of his earlier works; Tragedy and Hope and The Evolution of Civilizations. Quigley's observations on the uses of war are penetrating. Throughout history, society's decisions regarding its weapons systems have been decisive in shaping human social, economic, and political decisions. Of special interest today is Quigley's division of western weapons systems over the last thousand years into five successive stages, each associated with different political system. In Quigley's social analysis the dominance of democracy in the 20th century is attributable to the acceptance in the 19th century of a weapons system that favored democracy, the hand gun and rifle. In the consequent tilt toward an atomistic society, loyalties to the once strong social structures of family, church, and workplace break down.