This study investigates the tactical and operational levels of war. Initially a review of FM 100-5, Operations, is conducted to accurately define these two levels of war and point out the many distinctions or differences which U.S. Army doctrine recognizes between the two. Then two well-known historical examples, the British and the Germans at El Alamein in November 1942, and the Germans and the Soviets on the Eastern Front in February-March 1943 are investigated to determine if some of the differences between the two levels are more important than others. Additionally, an operational level exercise conducted at Fort Leavenworth in the fall of 1985 by the School of Advanced Military Studies is reviewed to support or refute the findings derived from case studies. This study concluded that, while there are many areas in which the differences between these two levels can be demonstrated or understood, the four most prominent functional areas demonstrating the critical differences are: intelligence, planning, maneuver, and sustainment. These four functional areas provide a framework for analysis to aid in studying these two levels of war.