MORTALITY. By Christopher Hitchens. Twelve. 128 pages. $22.99

The bottom line: Except for those struck down suddenly and violently, we all cross the threshold separating health and terminal sickness at some point. We all face oblivion (some confront it, some avoid it, some try to strike a deal), and the experience is colored by the degree of endurance we exhibit and the amount of productive thinking we are able to achieve.

It would be a stretch to say that fine artistic or literary expressions can ameliorate the distresses and discomforts that dying inflicts on its victims, but such expressions can aid those who have not yet shaken hands with the Reaper. A generous slathering of gratitude, therefore, is due to Christopher Hitchens, who entered “Tumorville” suddenly one June day in 2010 and died a year and a half later on Dec. 15, 2011.

He did not die with dignity, but in pain. He did not “lose his battle with cancer” (he never had a chance), he endured until he couldn’t. He did not go gently or willingly. He did not like dying very much at all and left us a small, final book, “Mortality,” advising us to avoid the whole endeavor if at all possible.

Religion was no comfort he sought. He had none, neither religion nor comfort. He had no use for others’ prayers, though he didn’t mind that people offered them; he was not quite the militant atheist many people supposed he was, merely a rational man who had no use for anything supernatural.

He was concerned with the natural. And it was entirely natural for him to live hard. “I have been ‘in denial’ for some time,” he writes, “knowingly burning the candle at both ends and finding that it often gives a lovely light. But for precisely that reason, I can’t see myself smiting my brow with shock or hear myself whining about how it’s all so unfair.” Rather, he has “succumbed to something so predictable and banal that it bores even me.”

In “Mortality” Hitchens eschews all sentimentality, all hyperbole, all self-pity. His clear-eyed confrontation, made explicit by his words, does not elicit the reader’s sympathy for his suffering; rather, it elicits sympathy for his thinking. And his writing.

Here is an example of dying that anyone — believer, nonbeliever, artist, soccer mom, Wall Street executive, hobo, athlete — can learn something from. The hypocrisies of religion are laid bare. “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,” Hitchens writes, drawing much of his material from a vast repertoire recollected despite the chemo fog he endured.

Religion, though, occupies only one chapter of this slim-yet-substantial volume. The other six complete chapters deal with relationships, hospitals and the brutal forfeiture of will they often require, his ongoing interests and activities in the world and the way his decades of impeccable journalism and opinion writing becomes relevant in the present.

He discusses (or at least mentions) such imposing figures as Nietzsche and Leonard Cohen, Karl Marx and W.H. Auden. He recalls favorite poems, applying their meaning to present circumstances. He pokes sardonically at his condition all the while maintaining a steady gaze at the privilege and destitution that surrounds him, that has always surrounded him.

Other contemplations pop up. He writes about writing, about finding one’s voice, and what’s worth writing about. “The most satisfying compliment a reader can pay is to tell me that he or she feels personally addressed,” Hitchens admits.

But it’s his friends, not his readers, who he appreciates most.

“My chief consolation in this year of living dyingly has been the presence of friends. I can’t eat or drink for pleasure anymore, so when they offer to come, it’s only for the blessed chance to talk.” Talking, he writes, is the most precious thing. “What do I hope for? If not a cure, then a remission. And what do I want back? In the most beautiful apposition of two of the simplest words in our language: the freedom of speech.”

The eighth chapter is an aggregation of fragments and notes Hitchens jotted down during his illness, ideas that were fleshed out in some cases, becoming part of earlier chapters, or necessarily left in their cryptic form. The entire book constitutes an unfinished symphony, its themes distinct, its tonality, despite the subject matter, determinedly presented in a bright major key.

“Hitch-22,” the memoir published just before his cancer cashed in its chips, offers the reader a whirlwind tour of a man with a brilliant mind and hunger for life. “Mortality” causes the reader to regret a great loss. For it was Hitchens who has provided a lucid analysis of our time, time and time again, railing one minute against Mother Teresa and Henry Kissinger, extolling the virtues of George Orwell or Thomas Jefferson the next.

Books are marvels. They provide an opportunity to span the ages and meld minds with someone who made a faraway effort to say something. Time becomes boundless, space meaningless, mortality insignificant. The reader and writer forge a mutual bond that opens a channel through which ideas travel. Warp speed. The result is a vital erudition. The knowledge informs who we are. At the end, when it’s our turn to meet the Reaper, it all vanishes forever, unless something is written down.

What a joy it is to be fed by the dead.

Reviewer Adam Parker is book page editor for The Post and Courier.