Operational art is a doctrinal term used by the United States US Army to describe the effort of military leaders to arrange military actions in pursuit of strategic objectives. In 1914, the German 8th Army in Eastern Prussia pursued the strategic goal of defending Prussia in order to enable decisive operations of German forces west of Germany. This monograph answers the question if the German 8th Army applied operational art as described in US doctrine today. First, the author describes and compares German operational thought in 1914 with todays US doctrinal understanding of operational art. The German political, social, and military constellations and their influence on German operational thought are of special consideration in this process. This section also considers the impact of German Auftragstaktik and US mission command on planning and execution of operations. Second, this monograph analyzes the German battles at Tannenberg 1914 through the criteria of risk, trust, and synchronization. These criteria encompass facets of German doctrine in 1914 and current US doctrine. At the same time they reflect aspects of the respective leadership philosophies of both countries. The author identifies that the German 8th Army applied at Tannenberg 1914 operational art as US doctrine understands it today. The German commander Hindenburg continuously arranged forces in time, space, and purpose while he pursued the strategic objective of the German Army High Command. Todays US operational art can be used to analyze and understand the German operations. However, the author identifies qualitative differences, especially in relation to risk acceptance, which can only be understood in relation with the German political and social circumstances in 1914.