Women made great spies because they were viewed as nonthreatening and docile. The majority of women spies were young, white, and unmarried because they had more freedom and time. However, there were also many slaves, and former slaves who worked as spies, such as Harriet Tubman, a former slave, who served as a Union spy, and a conductor of the underground railroad.
Spying was a risky business. In order to