Today in 1864, Rose Greenhow, perhaps the most famous of Confederate spies drowned in the Atlantic Ocean today. On a mission from Europe, her ship, the runner Condor ran aground while being pursued by a US warship. She took a small boat and that too capsized. Weighed down by a bag of gold tied around her neck that she smuggled from Europe, this pre-war grande dame of Washington society drowned.
Using her medley of connections in pre-war Washington, she obtained secret information about the movement of General McDowell's army and passed it on to Southern authorities, making it possible for the Confederacy to win the first battle of Bull Run.
There are two good introductory books that tell the story of Rose Greenhow's adventures. They are Alan Axelrod's The War Between the Spies and Harnett Kane's Spies for the Blue and Gray. I read the first book as part of my research for my second novel and I am currently reading the second book for my research for the third novel. Though not definitive, they give you a basic outline of Greenhow's espionage activities during the war.