Land warfare in the 21st century will be shaped by the cumulative effects of many revolutionary changes that have yet to merge in a clear or predictable pattern. This paper identifies three elements of change that are likely to have the greatest impact on the Army and the joint conduct of land warfare. First, the international system is undergoing its third major transition of the 20th century in response to the end of the cold war. Second, changes in military technology are culminating in what many believe will be a "military-technical revolution" that brings unprecedented depth and transparency to the battlefield. Finally, this paper cautions that change will inevitably coexist with at least three constants--the root causes of war, the nature of war, and the essence of fighting power. Preparation includes traditional non-quantifiable factors as much as technology. Leadership, courage, self-sacrifice, initiative, and comradeship under extreme conditions of ambiguity, fog, friction, danger, stark fear, anxiety, death, and destruction--all remain the coins of war's realm and no amount of technological advance will degrade their value. A central message of this paper is for strategists to carry the best of the present forward as we adapt to the revolutionary changes on the horizon. Land warfare will remain a vital component in the national military strategy, but only if we understand and respond to the forces that are shaping the battlefields of the 21st century.