Europe's Fate was at Stake is the first comprehensive English language study of the Prussian field marshal, Count August Neidhardt von Gneisenau (1760-1831). Using primary source material from archives and personal correspondence, and also previous German studies, including the foundational biographies of Georg Heinrich Pertz and Hans Delbrück, this work brings Gneisenau's influence on the development of the Prussian army to an English-speaking audience. It shows this development in the context of a life as a practical soldier and military thinker from the army of Frederick the Great through to the Waterloo campaign. The book takes the reader through the defeat by Napoleon in 1806 and subsequent resistance; the reform of the Prussian army under French occupation until 1812; and the Wars of Liberation between 1813 and 1815 when Gneisenau was the chief of staff to Prince Gebhard von Blücher. Overcoming the stereotypical portrayal in the pre-1914 German literature of Gneisenau as a dogmatist wedded to decisive battle and the annihilation of the enemy, the work shows how he took a pragmatic approach to the planning and conduct of strategy and operations.