Caffe Dante, in Greenwich Village. Photograph by Patti Smith

This piece is drawn from the postscript to “M Train,” which appears in the paperback edition of the book, published this week by Vintage.

I grabbed my brown watch cap, slipped on an old tweed jacket I bought in a street bazaar in Tangier, and walked over to the Caffe Dante. I read for a while and was about to scribble a few thoughts in the margin when I dropped my pencil. As I bent to retrieve it I was tapped on the shoulder by a stranger.

“I was wondering if you could recommend some books for me to read.”

I looked up at him a bit bemused. I was about to mention that there were no fewer than fifty of them cited in my current book, but I realized that would be presumptuous, as there was no guarantee he had even heard of it, let alone read it. Instead I wrote down a few titles on a napkin—“Suspended Sentences,” “Wittgenstein’s Poker,” “Shantytown,” “Heart of a Dog”—and handed it to him. Afterward, it occurred to me that I hadn’t written down the book that was open before me, “18 Stories,” by Akutagawa, nor the one in my pocket, “The Lover” by Marguerite Duras. Some weirdness on my part. A childish possessiveness—I had staked them as my territory, their atmosphere particular and concurrent to my own.

Unable to recall what I had been thinking, I returned to Akutagawa’s “Spinning Gears.” In the story, the writer is interrupted by a young reader who wants to meet him. The writer freezes. Snow begins to fall. The whole world is one wide sheet of paper and he dips his nib into the inky night as if to write one never-ending haiku dedicated to the absurdity of interruption.

I wondered if death is merely the same deal—life interrupted then rebooted as some Kafkaesque journey with several checkpoints. The hours melted into future hours, accelerating then slowing down for no apparent reason until it was suddenly evening. I sat on my bed waiting for “Luther” until I realized I was waiting on the wrong night. Despite myself, I got drawn into “Murder, She Wrote,” usually reserved for when I’m truly desperate_._ Jessica’s publisher was harping on the idea that she should somehow wrangle an invitation to a macabre celebration on the anniversary of the unsolved murder of an infamous Hollywood producer, certain that Jessica, with her effusive charm and uncanny skills, could snoop around, solve the damn thing, and then write a best-selling book about it. Jessica protested, reminding him that she was a fiction writer. But her publisher insisted, citing Truman Capote’s “In Cold Blood” as a model.

“Nonfiction crime sells,” he said, shaking his finger at her. “Look, Jessica, if that little guy can do it, you can do it.”

“Well, if you put it that way,” she said, still a bit leery.

And sure enough, in just one episode, she finagled her way into the party, solved the murder, and, just like that little guy Capote, wrote the book that became an instant best-seller.

Switching to the news provided a sober dose of hyperrealism followed by a wrenching documentary on the Amazon Delta zeroing in on capitalist entrepreneurs stalking rainforests with chain saws. I made a mental note to do productive things in the morning—disseminate the stacks of books that dominated my floor, finish the unfinished, walk a longer distance, and then fell asleep sitting up.

It was still dark when I awoke at the edge of a phantom hangover akin to the Electric Prunes song “I Had Too Much to Dream Last Night.” Disconnected scenes crisscrossing. Aerial views of urban decay, flagging palms, corporate safe houses; shadows of surveillance. Academies occupied by forces expurgating “The Metamorphoses.” Julian Assange gnawing the threads of a rotting veil, severing the net. I reached for my notebook to get it all down, a dream brushing against the backside of reality. This is how it ends; sun swathed in webs embroidered by extinct spiders; small heads bobbing in chlorine waves. Fishermen bewailing empty nets made by their own hand, just as their fathers and their grandfathers did, all the way back to the time of Jesus before he bade them to become fishers of men.

I went downstairs, careful to avoid the masses of books piled next to empty boxes, made a peanut-butter sandwich and prepared a pot of lemon, honey, ginger, and cayenne. The sun was rising over New York City. I opted for a stay-in Sunday. It used to be that I’d write for a couple of hours in Café Ino, later straighten my room, fill my thermos, and get ready for a new episode of “The Killing.” Only now, café gone, show cancelled mid-plot, I am left with the residue of the unresolved. On impulse, I decided to write to Veena Sud, the show’s producer, a fan letter of sorts, in gratitude for bringing us her vision of Linden and Holder. I was happily surprised when she wrote back to me and we continued to correspond. Some weeks later, she shared the news that “The Killing” would return for six more episodes, not quite enough to suspend time and examine the plot from several angles, but enough to know what happened next.

Veena kindly invited me to Vancouver to watch them shoot some scenes for the first episode. Unable to believe my good fortune, I swiftly accepted. Then just before the New Year she upped the ante, offering me a cameo. I had mixed feelings—namely, joy and horror. My sole experience acting for television was a small role as Cleo Alexander, a mythology professor at Columbia University, in the final season of “Law and Order: Criminal Intent.” Oblivious to the necessity of subtlety, I projected too strongly, if not theatrically, in rehearsal. Vincent D’Onofrio patiently counselled me by sharing an anecdote of his own experience while working with Stanley Kubrick. I learned this when delivering dialogue: pull your energy back a few steps, halve it—a slightly embarrassing but valuable lesson in restraint.

Photograph by Patti Smith

I received my script and working papers. I had envisioned I might play a street castoff or some homeless informer, akin to my naturally dishevelled appearance. But surprisingly I was given the part of Dr. Ann Morrison, neurosurgeon. Ten lines and a lab coat. It was all about the brain.

In late February, I flew to Vancouver. On the plane, I reflected on the fact that both my cameos were for favorite shows in the throes of cancellation. At the customs office, I was instructed to sit next to the actress Joan Allen, who was set to star in Season 4. As our working papers were scrutinized, I amused myself by conjuring the image of her rifling through classified files in “The Bourne Supremacy.”

Veena Sud introduced me to the director and we went over my lines before I met with the costume designer. My hair was wound in a bun and I was fitted with slacks and a trim blue flowered blouse to wear beneath my lab coat. They supplied me with my hospital badge, medical clipboard, and a pair of extremely sensible shoes. After a few adjustments, I was escorted to the set. There was a break in the action and I was allowed to enter the crime scene. The wall was smeared in blood—an ominous Rorschach butterfly above a spattered queen-size bed. I withdrew, then quietly observed my two detectives, as they readied themselves for work. Holder had the same restless energy off and on set. Linden stood by herself, with her head down. I watched her in silhouette, unruly strands from her ponytail obscuring her eye.

A few brief rehearsals were capped by sharing rice and beans from the canteen truck with Linden and Holder. I couldn’t bring myself to address them by their real names, but they didn’t seem to mind. Thus my imagination was not tainted with reality. Our scene was shot in a wide holding area outside the hospital I.C.U. We stood facing one another in the harsh fluorescent light. I was obliged to address my favorite detectives with dismissive authority, denying them access to my patient, the sole witness to a mass murder, and send them on their way. It was barely two minutes long, but those were two pure minutes embedded in their world. Before I left the set, Holder gave me his official calling card. When I got back home, I put it on my dresser, next to a small cabinet photograph of Eugène Delacroix.

From the book “M Train,” by Patti Smith, copyright © 2015, 2016 by Patti Smith. Published by arrangement with Alfred A. Knopf, an imprint of Knopf Doubleday, a division of Penguin Random House LLC.