The influence of space power pervades almost every sphere and level of human existence, from politics to military affairs to commercial activities to cultural mind-sets. Yet there is little to be found today in the way of coherent space power doctrine and strategy, particularly in national security circles. To what extent do our national interests rely on space? How shall we defend our interests in space and how shall we deny our adversaries the benefits of space power in time of conflict? How can we control and exploit the space environment? How can we effectively wield space power against the full spectrum of threats -- from the lone terrorist to global peer competitors? What should be our long-range strategy and objectives if our goal is to achieve and maintain long-term space superiority? The purpose of this paper is two fold: first, to illuminate the historical and ever-increasing importance of space in modern society; and second, to prescribe, in view of this importance, the foundations of a strategy for achieving lasting space superiority and ensuring national and world security.