As honest as Abraham Lincoln was, he was also an avid consumer of intelligence and a ruthless aficionado of clandestine warfare, willing to take chances to win the war. Delivering a colorful narrative of the heroes—and scoundrels—who informed Lincoln's generals, Douglas Waller profiles famed detective Allan Pinkerton; lawyer turned spymaster George Sharpe; heiress Elizabeth Van Lew, who ran a Union spy ring in her Richmond mansion; and Lafayette Baker, a dashing officer who assembled a retinue of disreputable spies, thieves, and prostitutes to root out traitors in Washington, D.C., but failed at his most important mission: uncovering the threat to Lincoln from John Wilkes Booth and his gang.

"[A] fast-paced, fact-rich account.... Douglas Waller has most skillfully aimed a spotlight on this neglected aspect of the Union effort. Civil War military history can never again be read or told in quite the same way."—Wall Street Journal