The brother of Friedrich Wilhelm Rüstow and Alexander Rüstow, Caesar Rüstow was one of the foremost experts of his time in the design and construction of military rifles, and the writer of several treatises on that subject, notably Die Kriegshandfeuerwajfen (Berlin, 1857-64). Both Alexander and Caesar fell on the field of battle in the war of 1866, Caesar at the Battle of Dermbach.