Sergei Olegovich Tretyakov was born on Oct. 5, 1956, in Moscow. His grandmother had worked for the intelligence services and his father for the Ministry of Foreign Trade, which posted him to Tehran, where Sergei spent his early childhood. While studying at the Institute for Foreign Languages in Moscow, he was recruited by the K.G.B.

Image Sergei Tretyakov Credit... www.PeteEarley.com, via Associated Press

“For me it was fascinating,” he said of the intelligence work, speaking to NPR.

He spent his first five years in the K.G.B. in Moscow sifting through Western publications for information of use to the government. In 1990 he was sent to the Soviet mission in Ottawa, where he recruited Canadian informants with an animus toward the United States.

After he defected, he lived in hiding with his wife and daughter, Ksenya, who also survives him. All three became American citizens.

When “Comrade J.” was published, Mr. Tretyakov began making public appearances. After that he lived more or less openly, under his own name and without protection, although when he traveled abroad he had an F.B.I. escort.

In “Comrade J.,” Mr. Tretyakov wrote a long statement explaining his reasons for defecting.

He said he switched sides because he had lost faith in the leaders who succeeded Mikhail S. Gorbachev. “I saw firsthand what kind of people were and are running the country,” he wrote, saying he believed they had enriched themselves and a handful of cronies. “I came to an ultimate conclusion that it became immoral to serve them.”

In a caustic aside, he noted that he had never met with the former Russian president, Vladimir V. Putin, a former K.G.B. officer, partly because they worked in different parts of the world, and partly because Mr. Putin was “never successful in intelligence,” and therefore never worked at headquarters. “He was always kept in a provincial K.G.B. station in a low and unimportant position,” he said.

Mr. Tretyakov also said that he defected so that his daughter might have a better life.

“No one recruited me,” he wrote. “No one pitched me. No one convinced me to do what I did.” He theorized that American intelligence officials never approached him because he was seen as an old-style K.G.B. officer.