This dissertation is a qualitative historical study that examines the state of morale of World War I soldiers as reflected in letters to the editor published in "The Stars and Stripes" newspaper between March 1, 1918, and November 15, 1918. The narrative includes extensive use of the actual words published in the soldiers' letters in order to evoke the spirit of the time and determine the probable state of morale of the soldiers. Morale has long been an important element of the effectiveness of an army during war. General John J. Pershing, Commander of the American Expeditionary Forces (AEF) during World War I, authorized publication of "The Stars and Stripes" newspaper to keep soldiers informed about news in the AEF and in the United States and to improve morale. The newspaper also provided a voice for soldiers and civilians so that they could publish stories, poems, artwork, and letters to the editor. The guiding question for the study was "How did letters that soldiers wrote to The Stars and Stripes newspaper during World War I reflect their morale?" Based on research that morale can be determined by using a pre-established set of qualifying parameters (themes), morale of the troops in the AEF was examined in published letters to the editor. The major source of the research was a book of facsimile copies of "The Stars and Stripes." Other primary sources were also used to discover indicators of morale in 1918 so that rubrics could be developed to classify letters according to themes. Thematic analysis was used to construct and evaluate rubrics to determine whether soldier morale was high or low in order to arrive at the conclusions of this study. "The Stars and Stripes" was truly the soldiers' newspaper and provided an outlet to improve morale, which was the purpose for its creation. The results of this study indicate that "The Stars and Stripes" positively influenced troop morale not only through positive experiences communicated by the soldiers but also by their ability to express frustrations and question military procedures outside the regimented Army structure. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]