The daughter of Joseph Henry, one of America's most renowned scientists, Mary Henry was 21-years-old when her family moved into the only castle in Washington, D.C., the Smithsonian Institution Building. A prolific writer and astute observer, Mary began recording a diary in 1858, including a daily log of her personal reflections, events at the Smithsonian and conversations she had shared with many of the most influential leaders in America. It would have been impossible for the youthful lady, filled with juvenile yearnings and wanderlust, to have imagined the unspeakable horrors that would soon fill the pages of her blank diary, as she penned her first entry in November 1858. Mary's entries include personal conversations with Abraham Lincoln, General Ulysses S. Grant, common citizens and captured southern troops. A staunch unionist and American patriot, the young woman's diary reveals the incredible dilemma held by millions of Americans throughout the war between the states - as she often sympathized with the southern plight, mourned Confederate causalities and criticized the Lincoln administration's every move. Though her writings provide one of the greatest insights into the Civil War in the past quarter-century, Mary's diary is far more than a collection of random thoughts on matters of science and politics. Her diary is a story of both a young woman and a struggling nation coming to age in the latter half of the nineteenth century.