On May 10, 1861, Captain Nathaniel Lyon marched out of the federal arsenal at St. Louis at the head of 7,000 Union Regulars and pro-Union volunteers to break up a Missouri State Militia encampment at Camp Jackson. Hostilities erupted and several civilians and soldiers died when opposing forces opened fire on each other. The unfolding of events afterward drove previously undecided Missourians to join either the Union or Confederate side. Receiving near dictatorial authority from the state legislature, Governor Claiborne Fox Jackson raised a Missouri State Guard force to "protect the State from invaders."

The War began in Missouri at the taking of Camp Jackson, and this book presents the history and context of this pivotal Civil War event. Contemporary illustrations provide detail to this complicated narrative, and care is taken to present these events in the context of the vibrant character and lifestyles of the people who participated.