Most think Friday the 13th is a day when bad luck peaks.

For Ray Naar, Friday April 13, 1945, was one of the luckiest days of his life.

On this date, Dr. Naar, 82, of Point Breeze, and his mother, father and brother were liberated after almost a year at Bergen-Belsen, the Nazi concentration camp in northwestern Germany where Anne Frank died of typhus in March 1945.

"You know the old [World War II] song 'Over There'?" Dr. Naar asked, going on to sing the song's lyrics: The Yanks are coming. The Yanks are coming.

"They came," he said, noting that Americans arrived in two jeeps and one tank while Germans were escorting 2,000 inmates to another camp, two weeks before the British liberated Bergen-Belsen.

Some of Dr. Naar's wartime experiences are trickled throughout his partially self-published historical adventure novel, "Rachamim: From Darkness Into Light."

Released over the summer by iUniverse, "Rachamim" marks the first time Dr. Naar, who has written books and articles related to his career, has dabbled in fiction. He's a clinical psychologist who has taught and practiced adult psychotherapy for 42 years.

"I always wanted to write a novel," he said.

"Rachamim" follows the story of freelance investigator and Holocaust survivor David Castro as he copes with lingering memories of his concentration camp experiences and military service and embarks upon a mission for a former CIA employer to uncover Nazi war documents.

Along the way, David encounters an array of characters ranging from a psychologist who helps him sort through his loneliness and mental anguish to a former SS colonel suspected of war crimes.

"I wanted as much as possible to go deeper into the characters," Dr. Naar said. "I wanted to make them come to life."

"Rachamim" is mostly fiction, yet some of David's childhood memories are based upon Dr. Naar's.

Dr. Naar was raised in Salonica, Greece. He recalls Salonica being a large and quite sophisticated Jewish community until a number of anti-Semitic laws were implemented, leading to the community's decline as Jewish families were sent away street block by street block to Auschwitz in Poland.

In 1943, Commandatore Giuseppe Castruccio, consul of Italy at the time, temporarily spared Dr. Naar and his family from a similar fate by helping them escape to Athens. One year later, they were arrested and taken to Bergen-Belsen.

Commandatore Castruccio was one of the people to whom Dr. Naar dedicated the novel. David's concentration camp experiences, however, are not excerpts from Dr. Naar's life.

In other parts of the book, Dr. Naar's life becomes the backbone of characters like David's psychologist, Dr. Rosen. Dr. Naar said the sessions Dr. Rosen has with David are all based on practices he has used with patients.

"All of the sessions have a sense of authenticity," he said.

"Rachamim" shares these characters' stories with readers through vignettes, or tracks.

"There are two tracks in the book," he said. "One is the adventure, the action. The other track is the redemption of David, who came literally from darkness into light."

Dr. Naar said he has always liked to write. "I think it's genetic," he said, adding that his mother enjoyed writing and his father was a satirical writer and a correspondent for a French and Belgium newspaper.

He found writing fiction less stressful than authoring books on psychology, but it presented other challenges. The novel took much longer to complete than he expected, taking seven to eight years. He credited his family, especially his wife of 55 years, Claudine, for keeping him motivated.

He presented the novel at a recent book signing at the Jewish Community Center of Greater Pittsburgh in Squirrel Hill. The book is available through barnesandnoble.com, amazon.com and at the University of Pittsburgh and Duquesne University campus book centers.

He doesn't know if he'll tackle another novel, but if anything, he doesn't plan to slow down anytime soon. He continues to see patients at his East Liberty office and is an adjunct professor at Chatham University.

Dr. Naar said someone recently asked him if he was retired.

His response? "Old people retire. I'm only 82."

Doug Oster writes a blog, "Growing With Doug," exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.