Back in 1985 in the Soviet Union, Merryl Goldberg was interrogated by the KGB three times, briefly kidnapped by the state security agency twice and put under house arrest once. She says it was worth it.

Today, Goldberg lives in Carlsbad and works at California State University San Marcos, where she’s a professor of music. But 41 years ago, she was a 26-year-old saxophone player tasked with a secret mission behind the Iron Curtain.

She and three bandmates from the Klezmer Conservatory Band in Boston, which performs traditional Yiddish and Jewish music, were set to meet and perform with refuseniks — Soviet citizens, mainly Jews, so named because they had been denied the right to emigrate.

It was no small job to visit refuseniks. The Soviet regime saw them as enemies of the state and, believing they would reveal state secrets, prohibited them from the leaving the country. Their restricted status turned many into dissenters and activists, often tailed by the KGB and getting their phone lines cut in an effort to keep their stories quiet.

If the KGB knew what Goldberg’s bandmates were doing, they could be deported — or worse.

So in classic spy fashion, the group devised secret codes to communicate with one another, hidden in plain sight, so the KGB would be none the wiser — using series of notes embedded in their sheet music.

“We made a nice little ensemble,” Goldberg said of the band. “The caveat is we had to do all of this in secret. We couldn’t tell anybody.”

It’s a wild tale, one that Goldberg recounts in a new book, “Notes of Deception,” she co-wrote with Vince Houghton, the director of the National Security Agency’s National Cryptologic Museum in Maryland.

Over 10 days in May of 1985, Goldberg and her bandmates — Rosalie Gerut, Hankus Netsky and Jeffrey Warschauer — traveled across the Soviet Union, meeting and sharing music with the refuseniks. Along the way, they were followed and questioned by KGB agents, were often separated from each other and slept in bugged hotel rooms.

In an effort to be as inconspicuous as possible, the musicians didn’t write anything down. Instead, the names of people they planned to meet, addresses and other important details were all hidden in the code of the music, its notes, chords and other symbols corresponding to letters of the alphabet.

When the KGB questioned the group and searched their belongings time and again, the officers had no idea what they were looking at, Goldberg recalls.

“Even a musician wouldn’t know that it was coded because it looked like 20th century music,” she said.

As the group learned the stories of the people they met, they encoded that into their music, too — ultimately smuggling it out of the country.

And when they returned to the U.S., they shared their stories with the public — meeting with journalists who wrote about the refuseniks, and collaborating with advocates who encouraged people to urge their elected officials to act.

They held a concert and press conference on Capitol Hill with a congressional caucus, and they met with then-Sen. Ted Kennedy, who advocated for refuseniks and ultimately helped a family the band met in the Soviet Union emigrate.

The trip and their advocacy were part of a growing movement of advocacy for refuseniks, building on nearly two decades of organized campaigns by groups such as the Student Struggle for Soviet Jewry and the Union of Councils for Soviet Jews.

The year Goldberg and her bandmates made their trip, hopes for progress were already rising.

As Mikhail Gorbachev became Soviet premier and promised new openness with a policy of glasnost, a slow thaw would begin toward free speech, human rights, the release of political dissidents and relaxed restrictions on emigration.

But that process would take years.