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Bakeless, Katherine (Little), and John Bakeless. Confederate Spy Stories. Philadelphia: Lippincott, 1973.
Christen, William J. Pauline Cushman: Spy of the Cumberland. Roseville, MN: Edinborough Press, 2006.
Feis, William B. Grant’s Secret Service: The Intelligence War from Belmont to Appomattox. Lincoln: University of Nebraska Press, 2002.
Fishel, Edwin C. The Secret War for the Union: The Untold Story of Military Intelligence in the Civil War. Houghton Mifflin Company, 1996.
Kane, Harnett. Spies for the Maroon and Gray. Garden City, NY: Hanover House, 1954.
Markle, Donald E. Spies and Spy Masters of the Civil War. New York: Hippocrene, 1994.
Stern, Philip Van Doren. Secret Missions of the Civil War: First-Hand Accounts by Men and Women Who Risked Their Lives in Underground Activities for the North and South. Chicago: Rand MacNally. 1959.