If the fictional exploits of government spies like Tom Clancy’s Jack Ryan and John Le Carré’s George Smiley don’t have the gritty realism some readers crave, they might try picking up a copy of Priceless: How I Went Undercover to Rescue the World’s Stolen Treasures, written by former FBI agent Robert Wittman. Now in paperback, the bestseller reveals details of several cases that Wittman worked while heading up the FBI’s Art Crime Team. His real-life experiences have all the ingredients of a high-octane spy thriller: mob connected thugs, police informants, millions of dollars worth of stolen art and FBI sting operations. The common thread being Wittman, whose chameleon-like ability to slip into different personas helped bring hardened criminals to justice and recover millions of dollars in fine art.

In an interview with NPR last year, the former senior investigator discussed a case in which he worked with Swedish authorities to recover a Rembrandt and two Renoir paintings stolen from the Swedish National Museum in Stockholm in 2000. Acting as a shady art dealer, he made contact with the thieves and worked to gain their trust. “I was undercover at that point as an authenticator for an Eastern European mob group,” Wittman explained. “After about two weeks with the thieves who were still in Stockholm, we negotiated the price [of the Rembrandt] down to $250,000. We actually had $250,000 in cash in the hotel room. We were bringing it back and forth to let them know it was real…And at that point, we were able to recover that $36 million Rembrandt,” he says. “Which was, probably the finest painting in the [Swedish National] Museum.”