Samuel Lyman Atwood Marshall, a journalist, influenced the United States Army in several ways beginning in 1943. First as a combat historian in World War II, then as a military critic, writer, lecturer, operations analyst, and consultant, he presented several practical and innovative ideas to the army. He pioneered the group after action interview technique for clearing up the confusing, often conflicting stories of participants in combat. As a result of his interviewing over 5 units in World War II, Marshall came to certain conclusions about what motivated Americans to fight. His subsequent experiences in other wars reinforced his theories. His ideas reached many soldiers and caused great controversy. Although he had great initial success in his efforts to reform the army, he spent his last years in a repetitious re-education process caused by such factors as institutional resistance to change. While some of his ideas have been incorporated into army policy, the most lasting influence has been through the education of the post World War II generation of junior officers who were stirred to articulate their ideas and experiences by their exposure to Marshall. These men are the key policy-makers of today's army.