August Otto Rühle von Lilienstern, born 1780, died 1847.

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.)

Lilienstern was a close friend of the landscape painter Caspar David Friedrich and his writing contributed to modern research of the artist.