Gathering secrets of the German submarines
In May 1918, the German submarine U-90 attacked and sank the U.S.S. President Lincoln. Lieutenant Edouard V.M. Isaacs was captured and taken prisoner. While a prisoner on board the submarine, Isaacs managed to gather information about German submarine movements for the United States. Lt. Isaacs eventually escaped from a prison camp in Germany and brought Germany's submarine secrets back to the Allies. He was awarded the Medal of Honor for his heroism. This is the citation that accompanied his award.
National Archives, Records of the Bureau of Naval Personnel