“Arcadia,” by Lauren Groff (Voice.)

Last year, I met a woman on the Metro.

She was sitting next to me reading a paperback copy of Lauren Groff’s “Arcadia.”

If you’re a book critic, you watch what people are reading in terms of your own survival. When the subway is full of riders staring off blankly or playing sudoku, I start to think about other things I could do for a living. Stuff envelopes at home? Shampoo dogs? 

Seeing someone with “Arcadia” made me think I might spring for a new book bag after all.

“I loved that novel,” I said to the woman.

“I’m having a lot of trouble with it,” she replied, as though we met on the Metro every day to talk books.

Her name was Ilene. She was reading “Arcadia,” she said, because of a review in The Post. I confessed with studied humility that I’d written that review and encouraged her to keep with it. But before we could say much more, our train got to Farragut North, and I had to dart off.

A charming, random encounter.

A few weeks later, I got an e-mail at work: “You probably won’t remember me, but I sat next to you on the Metro, and you noticed I was reading ‘Arcadia.’ ”

She’d stuck with it and ended up loving it.

The next month, she wrote again: “Several of my friends read or are reading ‘Arcadia.’ We thought we’d get together to discuss, and would love it if we could convince you to join us for the evening.”

I was tempted. Julie Klam was worried: “I hope this doesn’t turn into a ‘Misery’-like scenario,” she warned me on Twitter, invoking the image of Kathy Bates. “Tape a wire on your chest.”

Another friend tweeted, “I think you need a safe word.”

Nonsense. It took us many months — because I kept losing her e-mail address or dropping the ball — but Thursday night, we finally got together at her stately house in Chevy Chase: Ilene, eight of her friends (all women except for one husband), my wife and I. Some were lawyers. At least one was a stay-at-home mom. All were insatiable readers.

We ate pad Thai prepared by the housekeeper and then retired to the living room with chocolate-chip cookies.

What a delight to talk with real readers about their reactions to this lovely novel. They explained what moved them and what troubled them, and how their impressions evolved. One woman thought the commune setting sounded otherworldly; a woman from Vermont said it seemed pretty familiar. The discussion was fast-paced and engaged. I was in heaven. (How on Earth were we tricked into giving up evenings like this to sit alone at our computers “liking” one another’s cat photos? Or is that just me?)

As the discussion wound down, they started asking me about my job.

“How many books do you get every week?” One hundred and fifty a day.

“How do you pick which ones to review?” By the covers.

Then I gave a brief rundown of some of my favorite novels so far this year:

“The Unlikely Pilgrimage of Harold Fry,” by Rachel Joyce (Random House.)

That presentation sparked more discussion of other books we’ve enjoyed. Everybody loves everything by Strout. Someone was surprised by how funny Oates was at Politics & Prose. Several of us adored “The Unlikely Pilgrimage of Harold Fry,” by Rachel Joyce. One woman (and I) thought Gary Shteyngart’s “Super Sad True Love Story” was hilarious; another woman loathed it. One of the members constantly tapped away on her iPad, quickly supplying any title or name we couldn’t remember.

At 10:30, when they started to say good-bye, I couldn’t believe we were already done. “No, wait, there’s so much more!” For this book critic, who spends far too much time holed up at his desk fending off publicists’ pitches and proofreading quotations and revising schedules, it was the kind of rare evening that restores one’s faith in the health of our literary culture. Maybe everything’s going to be okay after all.

And the chocolate-chip cookies were delicious.