This is a new biography of Dr. Samuel A. Mudd, the young Southern Maryland country doctor who provided medical assistance to John Wilkes Booth following Booth's assassination of President Abraham Lincoln in 1865. It contains new information never published before on Dr. Mudd's life, including his education at Georgetown College and the University of Maryland medical school, his marriage and family life, his several meetings with John Wilkes Booth, his arrest, trial and conviction, his four-year imprisonment at the Fort Jefferson military prison in the Dry Tortugas of Florida, his failed escape attempt and punishment in the dungeon, his heroic work during a yellow fever epidemic at the prison, his life after being pardoned, and his death as described by his daughter who was at his bedside.