Only seventeen years after the establishment of the Army Nurse Corps (ANC), America entered into a global conflict known as World War I. It was a short period, less than two years until the Armistice in 1918, but the demands on nurses were profound. The ANC grew from 403 members to over 22,000 utilizing a significant portion of all the professional nurses in the United States. Their willingness to volunteer was the blueprint for how nurses would answer the need across the 20th century when the patriots responded to a call to arms in support of our Nation and freedom around the world. Recognition of the valuable role nurses played during the war led to the establishment, also in 1918, of the Army School of Nursing, a highly respected and unique institution that set exacting and enduring standards of quality. In dedicating this commemorative publication to all Army nurses who served during the First World War, the Office of the Surgeon General and the U.S. Army Medical Command pay tribute to the significant contributions that the Army Nurse Corps made to the advancement of military medicine 90 years ago.