This series contains materials originating from Gary Hansen's father, Clarence J. Hansen, including a journal and other items brought home from his World War I service as a Field Artillery Officer in the American Expeditionary Forces in France. After the Armistice in November 1918, his unit traveled into Germany as part of an occupying force. His unit sailed from France to New York in the spring of 1919 where he was mustered out of the Army and returned home. It also contains a 30 plus page account of his wartime experiences, including a typescript version of his journal and a speech that he gave on Memorial Day in 1952 to students at Ben Lomond High School in which he talked about his wartime experiences.

The section also includes a 26 page account prepared by Dr. Hansen of the World War I nursing service of his aunt, Ruth Hansen Bruerton. He prepared and submitted this document about her and the Lt. C.J. Hansen document for inclusion in the national Veterans History Project.