The early mobilization of Union volunteers, Northern and border state support for the war effort, the movement of troops to defend Washington, D.C., from an expected Confederate attack, the "rescue" of the U.S.S. Constitution, raids on secessionist farms in Maryland, and life in the troubled city of Baltimore are just a few of the topics highlighted in his diary.
Reynolds included many insightful details about soldier life and material culture during the period. Army discipline, religious practices, soldier-civilian encounters, training, rations, humor and numerous other aspects of the soldier's existence were deemed noteworthy.