Prussian officer, joined Scharnhorst's Academy for Officers in the same class as Carl von Clausewitz. Later, they both taught at the Prussian General War School, which would become the Prussian War Academy, and Rühle became Clausewitz' second successor as its director. Rühle published many articles, kept official war diaries, and wrote a two-volume Manual for the Officer for Education in Peace and for Use in Action (Handbuch für den Offizier zur Belehrung im Frieden und zum Gebrauch im Felde), published in Berlin in 1817 and 1818.
Lilienstern and Clausewitz, teaching at the same school at the time of publication of this manual, were in agreement on many points. (That is, literally a "two-struggle," usually translated into English as "duel," though in fact the imagery and metaphor that Clausewitz pursued was a wrestling match) Clausewitz made these ideas famous in his book On War.