A year ago the Chief of Staff of the Army initiated the Army After Next Project (AANP) as a means of stimulating constructive thinking about the Army's future throughout the service. AANP has quickly developed into a primary vehicle for long-range planning. Under the leadership of the Training and Doctrine Command (TRADOC), the AANP has conducted an ambitious program of studies, symposia and workshops, culminating in a Winter War Game and Senior Seminar held at Carlisle, January 27-February 6, 1997. A key line of initial inquiry for us has been to forecast the nature of the future security environment in which the Army will operate. That is the task Dr. Steven Metz set for himself in this monograph. In the pages that follow he propounds "currents of change" that will determine the future and sketches a series of plausible future security systems. Each system is characterized by the forms of conflict that will dominate it, the major strategic issues the United States might face, and the resulting military implications. While Dr. Metz's analysis leads to observations certain to be controversial, he illustrates quite clearly the primacy that environmental context will have in shaping our national security outlook and military strategy. Thus, Dr. Metz's observations on trends and systems warrant careful consideration as national policymakers and the Army's leaders build the military force of the future.