As he did in his highly acclaimed "George Washington, Spymaster", author Thomas B. Allen digs back through historical records to present a famous historical figure in a new light. Readers discover that Harriet Tubman - well known to them as an ex-slave who led hundreds of her people to freedom along the Underground Railroad - was also a spy for the Union Army. More specifically she worked behind Confederate lines in South Carolina getting information about troop movement and Rebel fortifications from slaves that she was leading to freedom on the Underground Railroad.She also recruited former slaves for Colonel James Montgomery, a Union officer who was raising an all-black brigade for a raid up the Combahee River to attack plantations in South Carolina. The report on the raid to Lincoln's Secretary of War stated: 'This is the only military command in American history wherein a woman, black or white, led the raid and under whose inspiration it was originated and conducted.' The raid was the first of several aimed at eroding the plantation system, the economic backbone of the Confederacy. The action is set within the context of Tubman's background as a slave in Maryland, her daring escape, her work with the Underground Railroad, and her association with John Brown and other abolitionists, all of which helps make her the invaluable scout (spy) known to the Union Army as Moses.