Rempe initially served as a cavalryman in the 35th (1st West Prussian) Field Artillery of the XX Armee-Korps, fighting in several bloody and significant battles against the Russians on the Eastern Front. In 1916, he exchanged his spurs for the cockpit and transferred to the Western front. Flying specially built planes for reconnaissance work was dangerous duty, but Rempe served in the open cockpits, flying at altitudes high and low to provide detailed intelligence information for the German army. He knew many of the pilots who flew in both fighter and reconnaissance planes, including Manfred von Richthoven - the Red Baron.

Unlike so many of his fellow pilots, Rempe survived several crashes, and was shot down over Reims, France in March of 1918. At war's end, Rempe returned to a defeated Germany in the midst of turmoil and revolution and served briefly in a Freikorps (Free Corps) regiment dedicated to preserving the new government in Weimar against German Communists. Seeking a new beginning, he arrived at Ellis Island in the spring of 1923 to start his life as an American. He brought with him flight reports, other miscellaneous documents, and scores of remarkable photographs documenting his wartime service, most of which are published here for the first time.

During 1956, the last year of his life, Rempe penned a brief memoir of his World War One service which, together with the photographic record, forms the basis of From German Cavalry Officer to Reconnaissance Pilot. Using primary and secondary sources Dr. Paul Rempe provides insight into the grim realities of Leonhard's war while his father's own memoir recalls his special comradeship with his fellow soldiers and airmen.

From German Cavalry Officer to Reconnaissance Pilot adds substantially to the growing literature of the First World War, and paints a unique and compelling portrait of a young German caught up in the deadly jaws of mass industrialized war.