Mine is not a normal job. I am always grateful for that. It has taken me to fascinating places, allowed me to witness momentous events and meet remarkable people. I am extremely fortunate.
There are many bad people in this world, but few are truly evil. Breivik is. He is not a genius, far from it, he was a drop-out in mainstream education. But he schooled himself, meticulously, in the science of terror. A masters degree in the methodology of taking lives.
For five years he locked himself away and studied. His final thesis was his "manifesto", it ran to 1500 pages but it was a flimsy work. A cut-and-paste Wikipedia job. He knew who he wanted to hate and he searched hard on the internet for the reasons.
He assessed the pros and cons of all the world's major terror groups, but developed a particular admiration for al Qaeda.
He learned all about building a bomb. Using google translate, he interpreted instructions posted by islamic fundamentalists. The very people he so despises were his tutors. Anders Breivik is a tangle of contradictions and hypocrisy.
He studied the structure of the building he planned to strike. Determined he would raze it to the ground, he measured the pillars and strengthened one side of his van to ensure the blast would be targeted precisely.
What was he thinking as he assembled all this? On the quiet weekday mornings as he welded the panels together or drove off to pick up more fertiliser. With his strike still months or years away, was there never a moment where he doubted himself?
He says he worked hard to change his character completely. Through years of meditation he "hammered out all normal emotions". He claims to no longer experience joy, sorrow, happiness or fear. And in that respect at least, I believe him.
Breivik sat in court and talked with precision and lucidity about shooting teenagers on the Island of Utoya.
He went into detail that there is no need to repeat, but what was more sickening than the content was the delivery. He did all but cross his legs, swing an arm over the chair and light a cigarette as he described executing scores of youngsters, some paralysed by fear.
He had the gall to feel self-pity. He had not wanted to shoot so many, he said. He had hoped that the panic would drive most of them into the water and they would die by drowning. But they did not. So he had to keep firing. How inconsiderate of them.
Perhaps the most miserable aspect of his endeavor was the fact that he used trust as a weapon. He conned his way onto the island by posing as a policeman, offering information and protection after the explosion that had just rocked Oslo (his bomb).
Once his killing spree was underway he coaxed the terrified youngsters out of hiding by shouting "where's the terrorist? Which way did he go?", relieved, they emerged, and he shot them.
What an awful, sniveling, despicable human being he is.
Breivik is confident, almost cocky, in the witness box but it cannot last. This trial has nine weeks to go, and he will crack soon, for sure.
Everything he says under questioning relates to his "manifesto", his magnum opus of twisted politics and deluded self-belief.
The prosecution have allowed him to cling to that this week, but when the four forensic psychologists, who have been listening and watching intently get hold of him I am sure he will fall apart.
With his comfort blanket removed perhaps he will open his mind to the enormity of what he has done. I hope so. Norway needs to see this man implode.
People like Anders Breivik are rare, thank goodness, but lessons can be learned from this. Not just the usual enquiries like police response and social service monitoring.
One troubling aspect of Breivik's preparation was the part played by computer games. He locked himself away for a year playing "warcraft" fantasies online. He spent every waking minute of every day in a parallel world, where he was God and his actions had no consequences.
He said it had no part in the planning of his attacks, but when someone removes themselves from society so completely, for so long, can they really re-emerge unchanged?
He graduated to war simulators, "Call of Duty" was his favourite. He used it, he said, to ready himself for the gun battles he thought he would encounter with armed guards as he parked his truck bomb. The holographic imagery on screen, he believed, was the perfect preparation.
I am no fan of gaming, I never have been, but I can see why my kids enjoy it at times. It troubles me, though, that we simply accept the fact such graphic brutality is used as entertainment.
I am flying home now. Looking forward to seeing my children after a long and draining week on the road. I am tired but I'll endeavour not to be grumpy - I have just experienced a sharp reminder of the important things in this fragile life.
I am looking out of my aircraft window at a snowy Norway. It's unseasonably cold for this time of year. It seems almost appropriate somehow, as the whole country has felt a sinister chill over the past week, but it's handled itself with astonishing dignity.
What a wonderful, liberal, comfortable society it is - and will continue to be, despite the dreadful efforts of one pathetic little man.