Talking to Adrian d'Hage can be a disorienting experience. In the classic words of Darryl Kerrigan, he's an ''ideas man''.
From the threat of an Iranian dirty bomb and the evil of organised religion to the sophistication of Inca technology via a brief diversion into the chemistry of photosynthesis, the ideas come thick and fast.
They are obviously the product of a fertile writer's imagination but also owe much to d'Hage's unusually eclectic background.
After North Sydney Boys High School and Duntroon, d'Hage commanded a platoon in Vietnam, for which he won the Military Cross. Later he headed up the Australian Defence Force's counterterrorism planning for the Sydney Olympics. Along the way he completed degrees in theology (which persuaded him to abandon his Christian beliefs) and oenology (which didn't persuade him to abandon his love of wine).
Currently, he is a PhD scholar at the Australian National University (ANU) researching the influence of religion on US foreign policy in the Middle East. And he writes. The Inca Prophecy is his fourth thriller and reflects many of his preoccupations and experiences.
A boy's own romp centring on the race to unlock an ancient cataclysmic prophecy, the action veers from a nuclear-armed Iran to the Vatican to the ruins of Machu Picchu. But d'Hage says there is more to The Inca Prophecy than simple derring-do by his CIA-hero character, Curtis O'Connor.
''It's written as a warning to our species,'' he says. ''Very few reviewers of my thrillers pick up on the subliminal messages. There's the lighter side - the Indiana Jones side - of the novel but, based on my background as a counterterrorist chief, it also takes you deep inside the Iranian Revolutionary Guard.''
In the lead-up to Sydney 2000, d'Hage was paid to imagine what horrors extremists could inflict on the city during the Olympics. He has put that experience plus his studies at ANU's Centre for Arab and Islamic Studies to good use in dreaming up hellish scenarios in The Inca Prophecy.
''I couldn't write these books at 25 or even 35,'' he says. ''I'm one of those that needs life experience. Some authors are born with it and can turn out a bestseller at 25. I'm not one of those.''
The Inca Prophecy takes readers inside the regime of Ayatollah Khamenei and Mahmoud Ahmadinejad but the Iranian Revolutionary Guard is the group that we really should fear, he says.
''Just as there are black operations within the CIA that the president or vice-president don't have the faintest idea about, so, too, there are operations in Iran.
''Should a nuclear device fall into the hands of terrorists, it puts the suicide bomber into an unbelievable new dimension. To the average punter this is cloud cuckoo land, but it's not. If they master this, they could wipe Sydney off the map.''
D'Hage paints a nightmare picture of hundreds of thousands of dead and dying and a nuclear winter to follow. And he points out that it is fundamentalism of all stripes we should be wary of and which could light the touch paper of any number of doomsday scenarios.
''Unless we get along and move towards not tolerance but acceptance of different cultures then the extremist elements of Islam, Christianity or Judaism will take us over the cliff. Religion is an accident of birth. We need to accept that and get along.''
D'Hage was brought up in Mosman in a fiercely traditional Catholic home, but it was not until about 30 years later, when he was a brigadier in the ADF, that he ''got the call'' to study for the priesthood.
For eight years he headed up the ADF's media department by day and studied theology at night, only to become ''totally disillusioned'' with all religion. ''The problem is the exclusivity - that we Christians have the only answer and must convert everyone else, or the fundamentalist Muslims have got to make everyone submit to sharia law, or the orthodox Jews who won't give up one centimetre of East Jerusalem,'' he says.
''What a load of balderdash. What sort of god would produce 7 billion people and say, 'You Christians are OK, but the rest of you are stuffed'? Not any sort of god that I want to know.''
This is vintage d'Hage, who, when recently asked to describe himself in three words, replied: ''My own man.''
He adds: ''I see myself as somebody who has had a very fortunate life and it's now my turn to put back in.
''If I can foster some debate about the stupidity of one religion being superior and the dangers that will lead us into then I'll be happy.''
The Inca Prophecy by Adrian d'Hage is published by Michael Joseph, $29.99