Christopher Hitchens began his memoir, “Hitch-22,” on a note of grim amusement at finding himself described in a British National Portrait Gallery publication as “the late Christopher Hitchens.” He wrote, “So there it is in cold print, the plain unadorned phrase that will one day become unarguably true.”

On June 8, 2010, several days after the memoir was published, he awoke in his New York hotel room “feeling as if I were actually shackled to my own corpse. The whole cave of my chest and thorax seemed to have been hollowed out and then refilled with slow-drying cement.” And so commenced an 18-month odyssey through “the land of malady,” culminating in his death from esophageal cancer last December, when the plain unadorned phrase that had prompted him to contemplate his own mortality became, unarguably, true. He was 62 years old.

“Mortality” is a slender volume — or, to use the mot that he loved to deploy, feuille­ton — consisting of the seven dispatches he sent in to Vanity Fair magazine from “Tumorville.” The first seven chapters are, like virtually everything he wrote over his long, distinguished career, diamond-hard and brilliant. An eighth and final chapter consists, as the publisher’s note informs us, of unfinished “fragmentary jottings” that he wrote in his terminal days in the critical-care unit of the M. D. Anderson Cancer Center in Houston. They’re vivid, heart-wrenching and haunting — messages in a bottle tossed from the deck of a sinking ship as its captain, reeling in agony and fighting through the fog of morphine, struggles to keep his engines going:

“My two assets my pen and my voice — and it had to be the esophagus. All along, while burning the candle at both ends, I’d been ‘straying into the arena of the unwell’ and now ‘a vulgar little tumor’ was evident. This alien can’t want anything; if it kills me it dies but it seems very single-minded and set in its purpose. No real irony here, though. Must take absolute care not to be self-pitying or self-centered.”

“The alien was burrowing into me even as I wrote the jaunty words about my own prematurely announced death.”