Mr. Hitchens is gaunt these days, no longer barrel-chested. His voice is softer than it used to be, and for the second time since he began treatment, he has lost most of his hair. Once such an enthusiastic smoker that he would light up in the shower, he gave up cigarettes a couple of years ago. Even more inconceivable to many of his friends, Mr. Hitchens, who used to thrive on whiskey the way a bee thrives on nectar, hasn’t had a drink since July, when a feeding tube was installed in his stomach. “That’s the most depressing aspect,” he said. “The taste is gone. I don’t even want to. It’s incredible what you can get used to.”

But in most other respects Mr. Hitchens is undiminished, preferring to see himself as living with cancer, not dying from it. He still holds forth in dazzlingly clever and erudite paragraphs, pausing only to catch a breath or let a punch line resonate, and though he says his legendary productivity has fallen off a little since his illness, he still writes faster than most people talk. Last week he stayed up until 1 in the morning to finish an article for Vanity Fair, working on a laptop on his bedside table.

Writing seems to come almost as naturally as speech does to Mr. Hitchens, and he consciously associates the two. “If you can talk, you can write,” he said. “You have to be careful to keep your speech as immaculate as possible. That’s what I’m most afraid of. I’m terrified of losing my voice.” He added: “Writing is something I do for a living, all right — it’s my livelihood. But it’s also my life. I couldn’t live without it.”