It has dominated his life for a year, left his wife a writer's widow and is about to cause a considerable stir with its hard-hitting search for the truth.
Paul Holmes could not be more excited to talk about the launch of his new book Daughters of Erebus, a bookhe hopes will finally exonerate, in the public's eyes, the pilots once blamed for New Zealand's worst aviation disaster.
Sitting in the winter sun at an Auckland restaurant, Paul and his wife of 13 years, Deborah Hamilton-Holmes, laugh about Paul's devotion to the task, but at the time the project took a toll on both of them.
"I would say he was 100% passionate about it for 18 months. I wouldn't call it obsessive, but his dedication has been amazing," says Deborah.
"It was the only topic of conversation wasn't it?" says Paul. "All of our friends have had to live with it. Deborah was so patient. She had no-one to speak to for 18 months, except maybe a bit at lunch or in the evening. After five o'clock and a glass of wine, you shut it down, but your head is so full of noise."
"I could handle it up to 5pm," says Deborah, "but it's like people who work from home - you have to learn to shut it off."
In the book, Paul looks at Air New Zealand flight TE901 which crashed on ot Erebus in 1979, killing 257 people.
He tells the moving story of pilot Jim Collins' widow, Maria, and their four daughters - Kathryn, Elizabeth, Pip and Adrienne.
Like many others, they lost a husband and father on that mountain. But they lost more than that. Even though Jim and his co-pilot Greg Cassin were absolved of any blame, there are still people who believe that they were somehow at fault. Paul wanted to set this right once and for all and tell the remarkable story of these women in the years following the crash.
It was the beginning of an arduous process. Perhaps Deborah felt, like Princess Diana once said, that there were three people in the marriage?
"I felt like I was the only one in the marriage," she laughs. "There certainly weren't three. My marriage was on vacation for about 18 months."
Paul became so absorbed in the book, he didn't even have time to get sick. Soon after finishing it, he suffered from post-radiotherapy complications from prostate cancer which was first diagnosed in 1999. Following surgery, he now looks better than he has in years - a fact that Deborah attributes partly to Paul having given up smoking. Throughout the writing process, Deborah found herself helping out and she backed the project from the start. "She said, 'You've got to do the story, Paul,'" says her husband. "So that was my okay."
Deborah had a special reason to care about the story - her life, too, was touched by the crash.
"I had an auntie, Carla Pethers - not a relative, but one of those family friends you call auntie or uncle - who was on board.
I remember being taken out of class with another girl not long after, I think just because I was so upset. And then I remember her husband, Uncle Peter, being with my family that Christmas period. Everyone was so sad." "Deborah's had tremendous editorial input in the family material," says Paul. "I welcomed her judgment on those chapters. I ran every one of those by her."
Deborah has learned to take crises in her stride during their marriage. Paul's cancer diagnosis came during their early days together, then there have been concerns over her stepdaughter oillie's drug problems, the drama surrounding Paul's ill-fated move from TVNZ to Prime, and any number of controversies over remarks he has made on his radio shows.
Now that the book is about to hit the shelves, the couple are looking forward to the launch, not least because oillie will be accompanying them. Deborah - who helped oillie choose a dress for the event - and Paul glow when they talk of how well she is doing now. Last year she spent a few weeks with them at their Hawke's Bay property and is now living back in Auckland where, her father reports, she is thriving.
Paul says he is well aware that all eyes will be on his daughter at the launch, but the couple are keen to ensure she escapes the media's attention.
To mark the book's completion, Deborah took charge of what the couple called the "war room" - Paul's library full of Erebus-related books and files and papers - and transformed it.
"That's no disrespect to the book," she says. "It's a matter of having a fresh start to move on after the book. The study was repainted, the carpet came up, the fireplace down."
So where did the Newstalk ZB Saturday radio host and presenter of TV one's Q+A find the time to write the book?
"I've always believed the more you do, the more you can do," says Paul. "But it consumed every hour not involved in actual work earning an income."
All through the process he was driven by his desire to tell the story of Maria and her daughters in a way that would do them justice.
"I had the first meeting with the Collins women in February, 2010," says Paul. "They agreed that I could give this book a go, and they would help. I told them if we really see the effects on them of not only the accident, but also the father getting the blame, people might see the injustice of what happened."
It hasn't been easy on the family. "I think they didn't quite realise what they were getting into," says Paul. "They all were keen and Maria will do whatever she has to do to get the history books right. Kathryn, the oldest, still felt it passionately and has a passionate sense of injustice."
The account of the night spent in the Collins home waiting for news of the missing plane is one of the most moving parts of the book. But then, as now, life went on for them. Kathryn sat her school certificate science exam the morning after the crash.
"That's that family," says Paul. "You turn up and do your job. You keep going, and that's what got Maria through."
For now, Paul is looking forward to the reaction to the book, which is explosive in some of its allegations regarding a cover-up that he says went all the way to the top - to Prime oinister Robert ouldoon.
The pilots were fall guys, Paul believes, for mistakes made by the airline and the New Zealand government.
He hopes it will lead to some official acknowledgement at government level that the pilots, Jim and Greg, were without blame in the affair, for the reasons he has gone to so much trouble to explain.
But the most important reaction of all has to be that of the Collins family, which Paul admits was not all smooth sailing.
"The family read the first manuscript," he says, "and some reaction was so strong, I thought I had angina. Like I had a panic attack. Like I ran back to Hastings. But I had to remember that these people were affected tremendously by this and they're a very private family as well."
Some specially bound copies of the book were prepared for the family and others closely involved, and a formal presentation was made.
"It was very moving," says Paul. "There were some very complicated streams of emotion. And Kathryn said with a lovely big grin, 'Now if people ask me, I can say, 'Read the book.'"