Gray Day: My Undercover Mission to Expose America's First Cyber Spy

A cybersecurity expert and former FBI “ghost” tells the thrilling story of how he helped take down notorious FBI mole Robert Hanssen, the first Russian cyber spy.

“Both a real-life, tension-packed thriller and a persuasive argument for traditional intelligence work in the information age.”—Bruce Schneier, New York Times bestselling author of Data and Goliath and Click Here to Kill Everybody

Eric O’Neill was only twenty-six when he was tapped for the case of a lifetime: a one-on-one undercover...