Nothing sharpened Christopher Hitchens' mind like cancer.

He wrote the best, most piercing, most clarifying prose of his career as he faced down the specter of his own demise.

As he dealt with fatigue and nausea, with the anger, disgust and frustration that must accompany what he knew was a death sentence, Hitch poured it all into words that were as painfully honest as they were hilarious.

I sympathize afresh with the mighty Voltaire, who, when badgered on his deathbed and urged to renounce the devil, murmured that this was no time to be making enemies, he wrote in September 2010 in Vanity Fair, to those who hoped for a last-minute conversion to faith.

His illness was a terrible irony. Hitchens was at the peak of his career. For decades he had toiled in the margins of the intellectual elite, plunging into distant political conflicts that only a few Americans noticed, and hanging with the denizens of British literary journalism and highbrow fiction.

None of this paid very well, and despite Hitch's fancy accent, he did not come from money. But suddenly he got rich and pretty famous.

He was diagnosed with cancer just a few years after writing the 2007 bestseller God Is Not Great. It turned out that attacking George Bush, Bill Clinton and Mother Teresa got him nowhere near the notoriety that he won for taking on God. (Or god, as he always wrote it.)

Hitch became a constant presence on the debate circuit on the topic of atheism, a familiar face on the shows of Jon Stewart and Bill Maher (another vocal atheist) and a sought-after blogger, letter writer and columnist. (It seems there is no utterance of mine that isn't worthy of publishing, he told me, when I asked him to think about blogging for TheWrap.)

And so: Cancer was very ill-timed.

Rage would be beside the point, he wrote, on learning of his illness, in one in a series of columns in Vanity Fair that won him a national magazine award. Instead, I am badly oppressed by a gnawing sense of waste. I had real plans for my next decade and felt I'd worked hard enough to earn it. Will I really not live to see my children married? To watch the World Trade Center rise again? To read -- if not indeed write -- the obituaries of elderly villains like Henry Kissinger and Joseph Ratzinger? But I understand this sort of non-thinking for what it is: sentimentality and self-pity. Of course my book hit the bestseller list on the day that I received the grimmest of news bulletins, and for that matter the last flight I took as a healthy-feeling person (to a fine, big audience at the Chicago Book Fair) was the one that made me a million-miler on United Airlines, with a lifetime of free upgrades to look forward to ... To the dumb question 'Why me?' the cosmos barely bothers to return the reply: Why not?

WITHSTANDING THE GLOATERS

And of course, his religious detractors found much irony here, much about which to gloat.

But it was here where Hitchens rose to the challenge so few of us could imagine, using humor and a core intellectual honesty to face down the existential challenge that was suddenly of immediate relevance.

He absorbed many horrible insults, including those from observers who called his cancer some kind of divine retribution, something he somehow deserved.

He responded thusly in September 2010:

The vengeful deity has a sadly depleted arsenal if all he can think of is exactly the cancer that my age and former 'lifestyle' would suggest that I got. Why cancer at all? Almost all men get cancer of the prostate if they live long enough: it's an undignified thing but quite evenly distributed among saints and sinners, believers and unbelievers. If you maintain that god awards the appropriate cancers, you must also account for the numbers of infants who contract leukemia. Devout persons have died young and in pain. Bertrand Russell and Voltaire, by contrast, remained spry until the end, as many psychopathic criminals and tyrants have also done. These visitations, then, seem awfully random. While my so far uncancerous throat, let me rush to assure my Christian correspondent above, is not at all the only organ with which I have blasphemed ... And even if my voice goes before I do, I shall continue to write polemics against religious delusions, at least until it's hello darkness my old friend. In which case, why not cancer of the brain? As a terrified, half-aware imbecile, I might even scream for a priest at the close of business, though I hereby state while I am still lucid that the entity thus humiliating itself would not in fact be 'me.' (Bear this in mind, in case of any later rumors or fabrications.)

I never could decide whether to laugh or cry at this prose. In the end, I could only marvel at Hitch's ability to pierce the heart of his own mortality with such detachment and wit.

He always jumped into the middle of great moral debates. And he never took the side that was easiest to defend. In fact, it was easy to suspect that he liked to take the opposite argument -- just because.

This aspect of Hitchens -- the gadfly who loved the spotlight -- used to annoy me. I first remember seeing him a couple of decades ago on a talk show like Meet the Press, and he showed up a vision of scruffiness -- unshaven, and wearing Birkenstocks. I thought it stunk of anti-establishment grandstanding.

But I watched him over the years, and changed my mind when I got to know him during the release of my last book, Loot, about stolen antiquities. The fate of the Elgin Marbles -- the Parthenon sculptures taken to England a century and a half ago -- was another of his thankless causes, rooted in that core of intellectual honesty.

(The sculptures were taken by stealth. They belong in Greece. Not a lot of Brits spent their time saying so. Hitch did.)

He came to debate the topic with me at a New York Times lecture in 2008, and after beating up the British cultural establishment for about an hour, we headed out to a lunch at an empty Italian restaurant. It lasted for four hours, and he drank his way through many whiskeys and regaled the table with tale after ribald tale of his adventures.

It was one of the most memorables afternoons I've spent, ever.

Farewell, Hitch. We salute your brilliant mind, and a moral heartbeat that pulsed so strongly throughout.

And that pen. Oh how we will miss that pen.