Such a revolutionary change, however, was not automatically accepted by everyone and caused some consternation and debate among our NATO allies as well as the Army's sister services. The combat leader must know how to fight, how to marshal his courage and that of his soldiers, and how to bring his forces to bear at the critical time and place on the battlefield to impose his will on the enemy. Intellectual preparation begins with the textbook in the classroom but moves quickly to the map, to the sand table and then to the terrain. Intellectual preparation provides the mental basis for a broad perspective on warfighting by thoroughly and systematically searching military history while scanning the future for new technology and new concepts. Psychological preparation enjoins the leader to commit himself to professional excellence and to develop the tactical and technical competence which lay the foundation for both the leader's confidence and the unit's cohesion and successful performance.
Physical preparation is rooted in self-discipline.
While difficult to estimate the complexity of these tasks, it is impossible to exaggerate their necessity. Reading, understanding and applying doctrine are fundamental to the preparation for war. Doctrine describes how the Army will fight and support. Not only does doctrine govern training strategies in both units and schools, but it also directs force modernization efforts and helps orchestrate standardization and interoperability efforts with our sister services and our allies. As doctrine changes, so must the Army.