Harry, perhaps the cleverest man I ever met, left school in Belfast at 14, to do odd jobs for different employers.
In the dead of night he once transported an even deader pig (which had thoughtlessly perished of old age in its sty) into a Falls Road sausage factory, to be turned into a rather interesting pork-mince.
On another occasion, he stripped an old ship in Harland and Wolff shipyard, the only time he ever entered that Protestant bastion.But it was the building industry where Harry's genius prospered.
As a teenager, he saw the opportunity to supply workers - bricklayers, joiners, labourers - to builders: and he would sort out the tax. Which is to say, he would do no such thing, thereby making a great deal of money. For Harry would rather have rubbed broken glass into his eyes than pay a penny in tax.
Harry was a businessman who called himself a socialist, but one who made himself very rich from hiring out non-union labour.
Yes, there are a couple of contradictions there; but there should be, because Harry was the most contradictory man I've ever known.
He had been interned in the calamitous scoop of IRA suspects in August 1971: only he was no suspect, but the real thing.
A couple of months later, he was released to attend a family funeral, and someone arranged for him to come into the RTE studios where I then worked, to describe conditions in the camp.
And this is how I met him.
He arrived looking utterly broken. I asked him various questions about Long Kesh, which he seemed incapable of answering.
I gently probed and prodded, until Harry finally blew an oral fart into the microphone, and then vomited a proud gallon of stout - to which his stomach had grown unused - all over the studio floor.
And that, pretty much, was how our relationship developed. He endlessly led me into scrapes, from which I would barely scramble free. I once even found myself holding his IRA gun while talking to a British soldier ... (don't ask).
What he actually did in the IRA I never found out. He was far too bright to be a mere gunman; and anyway, his lot - the Official IRA - was drifting away from violence to embrace Soviet communism, in all its mutant silliness.
How could an intelligent man like Harry support such idiocy? Simple.
Because membership of the Official IRA conferred some protection on him from the Provisional IRA thugs who had taken over nationalist ghettoes.
Meanwhile, he conducted his own life in the undergrowth of an unabated - though non-violent - criminality.
He could conjure money out of thin air, but what he loved even more was - as a matter of principle: perhaps the only enduring one he had - conjuring fortunes out of the British Government.
Now the latter knew that the building trade in Northern Ireland was a vast scam, into which it was pouring colossal amounts of money, but none of it was coming back in tax.
So it assembled its best minds, who devised a foolproof system of certification which would finally bring order to the financial slum that was Belfast's building sites.
The new system was triumphantly introduced on a Monday. By Thursday, thanks to Harry, it lay in ruins. Initially, he worked the system to benefit the Official IRA, but - Harry being Harry - he was soon using it to enrich himself. Which prompted the OIRA to pay him an indignant visit, with guns, to teach him manners.
Ha! You could no more teach Harry McKeown manners than you could teach a fish how to tap-dance.
He was his own man: and a strangely cultured one too. He loved Victorian architecture, and he loved books, especially if they were mine: for he borrowed many, and returned none.
I lost contact with him after I left Belfast, but after more than a decade's silence, he phoned me again last year.
I visited him in his little flat in Warrenpoint (for he was as good at losing money as he was at making it).
My old friend, partner in a hundred lunatic escapades at the height of the Troubles, was dying.
That little stint stripping an old ship in Harland and Wolff all those years before, had done it for him. Asbestosis.
When I saw him for the last time a few weeks ago, he was in torment. Muscle wastage was destroying his body, and each breath was agony.
Yet when the end came, it did so peacefully and unexpectedly, his dutiful, loving daughter Eileen beside him.
The most amazing, most intelligent and the most compulsively unreliable man I have ever met; and typical Harry, he chose to be buried on the only day in the entire year when I couldn't make it to the funeral.
Ornery old bastard to the end.
Now rest in peace, friend of my youth: rest in peace.