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

Former FBI undercover operative O’Neill delivers an adrenaline-laced memoir of his clandestine efforts to bring down Robert Hanssen, FBI agent and double-agent Russian spy. His assignment: go undercover as one of Hanssen’s FBI reports in order to better gather evidence of his wrongdoing. O’Neill gives a nearly day-by-day account of his investigation, from his first uncomfortable interaction with his target in January 2001 to Hanssen’s downfall several weeks later. He is best at relating the tactical ins and outs of undercover work, like committing every interaction with Hanssen in detailed notes to his superiors and the highly choreographed efforts used to obtain crucial pieces of evidence (for example, a superior’s surprise offer to take Hanssen to the shooting range, for which O’Neill had to ensure Hanssen was sitting down, so he’d leave his phone behind). These moments are as compulsively readable as any thriller. O’Neill has a knack for ratcheting up tension so that foregone historical conclusions, such as Hanssen’s capture, feel like white-knuckle cliffhangers. The prose occasionally veers into potboiler territory (“This would be the first lie I ever told her. It would also be far from the last”), but the book largely succeeds in its efforts to create a tightly wound narrative around a remarkable investigation into a Russian asset. O’Neill’s page-turner deglamorizes undercover work while conveying the uncertainty, stress, and excitement that accompany a successful investigation. Agent: Becky Sweren, Aevitas. (Mar.)