The litigator ultimately found he liked the case, and wanted to prosecute more like it. In 1980, looking for a challenge, he accepted the job at OSI.

OSI employees, by Ryan's own description in Quiet Neighbors, were "an eclectic group" that included trial lawyers and recent law school grads, historians, intelligence analysts and criminal investigators.

Upon arriving at OSI, Ryan found he had an extraordinary job. In January 1980, the same month he joined the office, Ryan travelled with Walter Rockler, the man he would replace in March, to Moscow.

The trip's highlight was a meeting with a Soviet cabinet-level official. Ryan and Rockler broke the ice by lighting up cigarettes, even though Ryan, as he notes in his book, doesn't smoke cigarettes.

Ryan won from the Soviets the right to gather evidence and depose witnesses in their country, a privilege that was key to collecting evidence against alleged Nazis.

The work was intense and often emotional, as his office located Holocaust survivors and asked them to retell their experiences.

"You've got to have the detachment to talk to the survivor," Ryan says. "The prosecutor's responsibility is to assemble evidence and realize that can have an effect on the person who has been accused. That is not a role that emotion does well in."

Ryan left OSI in early 1983 to prepare a report for Attorney General William French Smith on Klaus Barbie, the onetime chief of the Nazi Gestapo in Lyon, France, widely known as "The Butcher of Lyon."

The U.S. had recruited Barbie into its intelligence service and facilitated his escape to Bolivia. As a result of Ryan's report, the U.S. issued a formal apology to France.

The attorney left the government for good later that year, spending much of the next 18 months writing Quiet Neighbors.

The book, which Demjanjuk lawyer Michael Tigar brought up while questioning Ryan in court last month, contains strong statements about the guilt of John Demjanjuk, who OSI successfully prosecuted as the infamous Nazi death camp guard "Ivan the Terrible."

Soviet records released in 1991 indicate Ivan may have been another man, and Ryan is no longer willing to say for certain that Demjanjuk was Ivan.

Now, Ryan says the book simply represents his thoughts and feelings as they stood 10 years ago. "It was a story that needed to be told," says Ryan, adding that he didn't make any money on the publication.

After he finished the book, Ryan and his wife, with two young children, decided they wanted to get away from Washington, and Ryan joined the Office of the General Counsel in March 1985.

But he never completely left his days at the Justice Department behind him.