I’m not used to running into the argot of my years in intelligence, least of all in a commercially available book. But here it is in The Billion Dollar Spy in spades — being in the black, a dangle, denied area, positive intel, identity transfer. Then came the shock of finding names of people I knew back in the day. The spy slang and familiar names made me ready to trust the author. This was going to be an authentic narrative, not another trivial tale novelized to attract readers.

And the content proved true; a genuine, thoroughly researched, and scholarly presentation of the reality of spying, backed by 14 pages of photographs and 30 pages of footnotes as readable as the text itself. The author, Pulitzer Prize-winner David E. Hoffman, is a seasoned reporter who maintains his journalistic objectivity and depends on fact. No need to dramatize; the story of what really happened is electrifying on its own.

Hoffman’s neutrality adds value in another way, too. The book is not an exposé written by an insider with an axe to grind. Hoffman’s vocabulary alone makes it clear he is an observer, not a participant. Most telling to me was his use of the article “the” before CIA. We in the business never use the article. To us, the intelligence agency acronyms — CIA, NSA, DIA — are personal names, like Sadie or Clyde.

The Billion Dollar Spy tells the story of Adolf Tolkachev, arguably the most fruitful undercover human source during the Cold War. Embittered by the destruction of his wife’s family at the hands of the Soviets and disillusioned by the falseness of Soviet propaganda and the harshness of life under Soviet rule, Tolkachev set out to do as much damage as possible to the USSR.

A senior engineer and specialist in airborne radar, he worked at the Scientific Research Institute for Radio Engineering (known by its Russian acronym, NIIR) and had access to its most sensitive information, including Soviet work on a look-down-shoot-down radar.

He spent more than a year trying to interest CIA, sequestered in the U.S. embassy in Moscow, before he got a response. CIA was, at the time, still in the thrall of James Angleton, the counterintelligence chief who was so suspicious of every potential agent who offered to work for the U.S. that he effected a stand-down.

After finally persuading the U.S. that he was the genuine article and not a dangle from the KGB, Tolkachev met clandestinely with CIA handlers 21 times over a period of six years. He photographed thousands of pages of highly classified documents and passed them, along with circuit boards and blueprints, to CIA. The U.S. government estimated that the information he provided saved at least $2 billion in the development of U.S. countermeasures. The most vital data would never have been known to the U.S. without Tolkachev’s spying.

The man who emerges from the written letters and lengthy op-notes Tolkachev supplied is a figure at once sad, energetic, realistic, and courageous. Uniquely touching to this reviewer was Tolkachev’s concern for his son, Oleg.

The most prized rewards CIA was able to supply Tolkachev were for Oleg — books, recordings of rock music, and, when Oleg was studying architecture, drafting pens and erasers. Tolkachev knew and accepted the danger to his own life. He harried his CIA contacts until they relented and gave him an “L-pill,” a cyanide capsule hidden in a fountain pen. He knew his chances for survival were slim.

The story is gripping in no small part because of Hoffman’s dependence on detail to create a here-and-now sense of reality. The city of Moscow comes to life in clipped descriptions of its streets and parks, well-known to Hoffman, who was once the Washington Post’s bureau chief there. We learn that CIA operatives were able to spot KGB cars because of the characteristic triangle of dirt left on their grilles through a flaw in KGB car-washing procedures.

We see up close techniques and equipment used to elude KGB surveillance — disguises worn under regular clothing that can be stripped off while riding in a car; the slowing of the car on a darkened street by use of the hand brake to avoid illuminating the taillights; the “jack-in-a-box,” affectionately known as the JIB, a birthday cake that opens to release a human-like figure that hides the absence of the agent who has just slipped out of the car.

Hoffman embeds Tolkachev’s story in the history of the period. Toward the beginning of the book, he sets the stage with details of the Cold War. In the middle, he suspends the narrative long enough to fill in the background of historical events told from Tolkachev’s point of view. With a deeper understanding of the man and his milieu, we are ready for the dénouement.

The ending of Tolkachev’s story is as suspenseful as the beginning. I won’t spoil it for readers except to say that the operation was betrayed by an American. That was the bitterest part of the story for this old intel hand to swallow.

I came away from The Billion Dollar Spy with a sense of hope and peacefulness. I’ve known all my adult life that the role of intelligence — to tell the truth in the context of war and diplomacy — is vastly underappreciated by the public. It can be no other way. It must remain carefully hidden or it will fail. Once the object of surveillance is aware he is being observed, he takes means to block the collector’s view.

But for the dedicated intelligence operatives who work harder than anyone else I know and routinely risk their lives in defense of our country, I find fulfillment in seeing our work described in full and praised. Once in a while, it’s nice to hear, “Thank you. And welcome home.”

Tom Glenn spent the better part of 13 years undercover in Vietnam collecting intelligence to assist U.S. combat forces and escaped under fire from Saigon when the North Vietnamese were already in the streets of the city. He is the author of 16 published short stories. His novel Friendly Casualties was published in 2012. Apprentice House brought out his No-Accounts last year and will publish The Trion Syndrome this fall.