Which is not to say, of course, that Hitchens refrains from going another round with his antagonists on the question of religious belief. At one point, he alights upon a Web contribution from a devout Christian gloating over what he took to be a cunning divine plan to smite Hitchens down, one of the faith’s most vocal critics — nothing less, the gentle correspondent divined, than “God’s revenge for him using his voice to blaspheme him.” Hitchens offers a typically patient, yet scornful reply:

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. 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 delusion, 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’m 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 fabrication.)

One appreciates the need for that closing disclaimer — even so, there’s something a bit incongruous about dressing down an unworthy online interlocutor at the end of one’s days. It’s not as though anyone’s mind is going to be changed. While the battle against superstitious folly does indeed span generations, that also means the odds against getting the last word are forbidding, to put it mildly. Far less gracious is one of the entries in his computer that Hitchens tossed off toward the end of his life, and that his editor has dubiously seen fit to reproduce here: “If I convert it’s because it’s better that a believer dies than an atheist does.”

Thankfully, though, Hitchens’ score-settling asides to the believoisie don’t take up the bulk of Mortality. The book serves chiefly as a prooftext for one of the subordinate arguments in God Is Not Great: that humanity will not conquer its own superstitious faith in the supernatural until it overcomes the fear of death. So, for instance, Hitchens becomes haunted by the idea of putting his pain-wracked body to some productive scientific use. He confesses that he was “hugely excited” to learn of immunotherapy protocols that promised an unlikely turnaround in his advanced cancer — until, that is, he learned that he lacked the proper DNA profile for the treatment to work. Likewise, a “60 Minutes” report on experimental stem-cell procedures enabling physicians to “grow” a new, healthy esophagus for cancer patients stirred fresh hopes — until Hitchens was informed that his disease had progressed too far to try any such treatments. “Analyzing the blues I developed during those lousy seven days,” he writes, “I discovered that I felt cheated as well as disappointed. ‘Until you have done something for humanity,’ wrote the great American educator Horace Mann, ‘you should be ashamed to die. I would have happily offered myself as an experimental subject for new drugs or new surgeries, partly of course in the hope that they might salvage me, but also on the Mann principle.” At last, he finds some accommodation for this thwarted hope, when his friend Francis Collins — the physician who wound up the Human Genome Project, and a firmly convicted Christian — undertakes a full sequencing of Hitchens’ DNA in the hopes that it might one day yield a therapeutic breakthrough. (Even this decidedly speculative prospect is clouded now, thanks to the ruling of a federal court putting a halt to government research involving embryonic stem cells.)

Hitchens also writes most movingly about the eventual arrival of the fate that his online Christian antagonists were urging on: the loss of his speaking voice. He delivers an unstinting appraisal of the degree to which he lived by the art of conversation — something that any visitor to his apartment-cum-salon in Northwest Washington could readily confirm: “All the rituals and etiquette of conversation, from clearing the throat in preparation for the telling of an extremely long and taxing joke to (in younger days) trying to make my proposals more persuasive as I sank the tone by a strategic octave of shame, were innate and essential to me. I have never been able to sing, but I could once recite poetry and quote prose and was sometimes even asked to do so.” Now, by contrast, his chemo-ravaged voice can’t even hold up his end of a chat: “If I want to enter a conversation I have to attract attention in some other way, and live with the awful fact that people are then listening ‘sympathetically.’ ”

Then, too, there are the far less joyous, infinitely more self-conscious etiquettes that govern speech shared between terminal patients and their would-be comforters — a ritual that Hitchens properly, and painfully, dissects as study in strategic evasion (about as far from vocal seduction, in other words, as one can imagine). Close relations and friends, he notes, “don’t really have the option of not making kind inquiries.” Still, when members of Hitchens’ inner circle opt for blunt truth-telling — as when one in their number asked, correctly as it turned out, whether Hitchens’ distress at missing a London family function stemmed from his deeper fear that he might never see England again, he finds himself taking inner umbrage: “I’ll do the facing of the hard facts, thanks. Don’t you be doing it too.” At the same time, though, Hitchens reflects: “I had absolutely invited the question.” In these and other plainspoken encounters with his medical handlers, Hitchens notes that “there was the unreasonable urge to have a kind of monopoly on, or a sort of veto over, what was actually sayable. Cancer victimhood contains a permanent temptation to be self-centered and even solipsistic.”

This is as good a point as any to break down the fourth wall of reviewing etiquette, and to note that like many other journalists in Washington, I was friendly with Hitchens, and had published his work at several of my former editorial perches — though our colloquies grew less frequent and more clipped as he emerged as an enthusiastic champion of the Bush administration’s 2003 invasion of Iraq. More to the point here, however, I can confirm just how impossible it was for Hitchens — even in the most taxing and awful throes of his illness — to succumb to the allure of solipsism or even garden-variety self-pity. Indeed, on the very next stop on that abortive 2010 tour for Hitch-22, in Chicago, he abruptly cut short his itinerary — not to absorb the devastating news of his illness, but to spend the day consoling a close mutual friend of us both who was enduring a hellish personal crisis of his own. It’s hard to call that act — which provoked no small amount of ire from his publisher, which knew only of the friend’s crisis at the time, and not Hitchens’ own — anything other than a demonstration of a truly amazing generosity of spirit (especially, one might add, in a city as resolutely petty and vicious as official Washington tends to be). In smaller things, too, Hitchens continued throughout his illness to observe an unfailingly expansive sociability even as his body was being eaten up from the inside. On New Year’s 2011, my then-wife and I hosted an open-house brunch; after much internal agonizing over the absurd distortions of normal social address that terminal illness seems to exact, I sent an invitation to Hitchens and his wife. He replied with regrets that he was to be out of town that day (in all likelihood, to seek more treatment in Houston, we both knew but did not say), and added, since he was writing on Christmas Day: “Compliments of the season, as Mr. Jefferson used to say at the Solstice.”

That salutation was a small flourish, informed of course by a gently secularist agenda, but the whole exchange again brought home to me Hitchens’ convivial, gracious nature: Here was a gravely ill correspondent, whom I had been leery in the extreme about imposing on at all, apologizing to me about his physical inability to honor a minor social invitation.

This was not, as Mortality fully attests, out of any disinclination to face the terrible facts, or any overdeveloped sense of English propriety. Rather, I think, Hitchens’ unshakeable will-to-sociability was his life — as he spells out beautifully in his panegyric for his failing voice:

All of the best recollections of wisdom and friendship, from Plato’s “Apology” for Socrates to Boswell’s Life of Johnson, resound with the spoken, unscripted moments of interplay of reason and speculation with others, that one can hope to hit upon the elusive, magical mot juste. For me, to remember friendship is to recall those conversations it seemed a sin to break off: the ones that made the sacrifice of the following day a trivial one[. . .]We may not be, as we used to boast, the only animals capable of speech. But we are the only ones who can deploy vocal communication for sheer pleasure and recreation, combining it with our two other boasts of reason and humor to produce higher syntheses. To lose this ability is to be deprived of an entire range of faculty: It is assuredly to die more than a little.

It’s well worth noting, in this regard, that Hitchens was able to use his voice in his dying moments, to singularly arresting effect, according to his literary executor Steve Wasserman: After trying, and failing, to write something down on a sheet of paper, he fell asleep briefly. When he awoke, he distinctly said the words, “Capitalism, downfall” — and repeated the phrase when his listeners asked him to. He died a short time later.

It’s bracing to think of how those final words went down with Hitchens’ lately acquired friends in the conservative movement. They may write it off as a momentary, disoriented reversion to his Trotskyist political past; no doubt they would have been much more comforted if he’d invoked instead the very same Supreme Being that Hitchens guaranteed he would never authentically appeal to. For my money, though, it’s both the mot juste and an overture to a conversation that Hitchens was presumably eager to renew. After all, as Montaigne also observed, “the premeditation of death is also the premeditation of liberty. He who has learned to die has also unlearned to serve.”