The classical military theorists and US Army doctrine emphasize the role of information within a conflict. The US Army's primary means for controlling and manipulating information is the doctrinal concept of information operations. However, there remains debate as to what IO is and how it is to be integrated into US Army operations. Case studies indicate that IO is more than media relations or psychological operations, and that information is an integral element of the convergent nature of conflict. Understanding the physical, informational, and cognitive domains of conflict and the IO doctrinal construct will facilitate the integration of IO into US Army operations.