A recent volume on the Harriet Tubman story, includes photographs.
Blockson, Charles L., "The Underground Railroad," in National Geographic Magazine, v. 166, No. 1 (July, 1984), p. 2-39.
Pictures and images of the underground railroad in a magazine format easily accessible at most local libraries.
Bradford, Sarah. Harriet Tubman, The Moses of Her People. Original version published privately by Sarah Bradford in 1869, more recent edition available from the Citadel Press, Secaucus, New Jersey.
The classic biography of Harriet Tubman, written by her friend Sarah Bradford to raise funds to help Harriet in her work and personal affairs.
Epstein, Sam and Beryl. Harriet Tubman: Guide to Freedom. Champaign, Illinois: Garrard, 1968.
For below level readers, a readable version of Harriet's story.
Ferris, Jeri. Go Free or Die: A Story About Harriet Tubman. Minneapolis: Lerner Publications, 1989.
Petry, Ann. Harriet Tubman, Conductor on the Underground Railroad. New York: Pocket Books (division of Simon & Schuster, Inc.), 1955.
For secondary grade levels, junior high and above, a readable account of the Harriet Tubman story, with incidents and journeys brought to life.
Robinson, Wilhelmena S. International Library of Negro Life and History. New York: Publishers Company, Inc., 1967.
A compendium of history and facts about African-Americans in a ten volume set. An excellent reference on people, places and history in Harriet Tubman's time, and in later years.