Within months, Clive’s confusion gave way to the agony, the desperation, that is so clear in Miller’s film. This, in turn, was succeeded by a deep depression, as it came to him—if only in sudden, intense, and immediately forgotten moments—that his former life was over, that he was incorrigibly disabled.

As the months passed without any real improvement, the hope of significant recovery became fainter and fainter, and toward the end of 1985 Clive was moved to a room in a chronic psychiatric unit—a room he was to occupy for the next six and a half years but which he was never able to recognize as his own. A young psychologist saw Clive for a period of time in 1990 and kept a verbatim record of everything he said, and this caught the grim mood that had taken hold. Clive said at one point, “Can you imagine one night five years long? No dreaming, no waking, no touch, no taste, no smell, no sight, no sound, no hearing, nothing at all. It’s like being dead. I came to the conclusion that I was dead.”

The only times of feeling alive were when Deborah visited him. But the moment she left, he was desperate once again, and by the time she got home, ten or fifteen minutes later, she would find repeated messages from him on her answering machine: “Please come and see me, darling—it’s been ages since I’ve seen you. Please fly here at the speed of light.”

To imagine the future was no more possible for Clive than to remember the past—both were engulfed by the onslaught of amnesia. Yet, at some level, Clive could not be unaware of the sort of place he was in, and the likelihood that he would spend the rest of his life, his endless night, in such a place.

But then, seven years after his illness, after huge efforts by Deborah, Clive was moved to a small country residence for the brain-injured, much more congenial than a hospital. Here he was one of only a handful of patients, and in constant contact with a dedicated staff who treated him as an individual and respected his intelligence and talents. He was taken off most of his heavy tranquillizers, and seemed to enjoy his walks around the village and gardens near the home, the spaciousness, the fresh food.

For the first eight or nine years in this new home, Deborah told me, “Clive was calmer and sometimes jolly, a bit more content, but often with angry outbursts still, unpredictable, withdrawn, spending most of his time in his room alone.” But gradually, in the past six or seven years, Clive has become more sociable, more talkative. Conversation (though of a “scripted” sort) has come to fill what had been empty, solitary, and desperate days.

Though I had corresponded with Deborah since Clive first became ill, twenty years went by before I met Clive in person. He was so changed from the haunted, agonized man I had seen in Miller’s 1986 film that I was scarcely prepared for the dapper, bubbling figure who opened the door when Deborah and I went to visit him in the summer of 2005. He had been reminded of our visit just before we arrived, and he flung his arms around Deborah the moment she entered.

Deborah introduced me: “This is Dr. Sacks.” And Clive immediately said, “You doctors work twenty-four hours a day, don’t you? You’re always in demand.” We went up to his room, which contained an electric organ console and a piano piled high with music. Some of the scores, I noted, were transcriptions of Orlandus Lassus, the Renaissance composer whose works Clive had edited. I saw Clive’s journal by the washstand—he has now filled up scores of volumes, and the current one is always kept in this exact location. Next to it was an etymological dictionary with dozens of reference slips of different colors stuck between the pages and a large, handsome volume, “The 100 Most Beautiful Cathedrals in the World.” A Canaletto print hung on the wall, and I asked Clive if he had ever been to Venice. No, he said. (Deborah told me they had visited several times before his illness.) Looking at the print, Clive pointed out the dome of a church: “Look at it,” he said. “See how it soars—like an angel!”

When I asked Deborah whether Clive knew about her memoir, she told me that she had shown it to him twice before, but that he had instantly forgotten. I had my own heavily annotated copy with me, and asked Deborah to show it to him again.

“You’ve written a book!” he cried, astonished. “Well done! Congratulations!” He peered at the cover. “All by you? Good heavens!” Excited, he jumped for joy. Deborah showed him the dedication page: “For my Clive.” “Dedicated to me?” He hugged her. This scene was repeated several times within a few minutes, with almost exactly the same astonishment, the same expressions of delight and joy each time.

Clive and Deborah are still very much in love with each other, despite his amnesia. (Indeed, Deborah’s book is subtitled “A Memoir of Love and Amnesia.”) He greeted her several times as if she had just arrived. It must be an extraordinary situation, I thought, both maddening and flattering, to be seen always as new, as a gift, a blessing.

Clive had, in the meantime, addressed me as “Your Highness” and inquired at intervals, “Been at Buckingham Palace? . . . Are you the Prime Minister? . . . Are you from the U.N.?” He laughed when I answered, “Just the U.S.” This joking or jesting was of a somewhat waggish, stereotyped nature and highly repetitive. Clive had no idea who I was, little idea who anyone was, but this bonhomie allowed him to make contact, to keep a conversation going. I suspected he had some damage to his frontal lobes, too—such jokiness (neurologists speak of Witzelsucht, joking disease), like his impulsiveness and chattiness, could go with a weakening of the usual social frontal-lobe inhibitions.

He was excited at the notion of going out for lunch—lunch with Deborah. “Isn’t she a wonderful woman?” he kept asking me. “Doesn’t she have marvellous kisses?” I said yes, I was sure she had.

As we drove to the restaurant, Clive, with great speed and fluency, invented words for the letters on the license plates of passing cars: “JCK” was Japanese Clever Kid; “NKR” was New King of Russia; and “BDH” (Deborah’s car) was British Daft Hospital, then Blessed Dutch Hospital. “Forever Today,” Deborah’s book, immediately became “Three-Ever Today,” “Two-Ever Today,” “One-Ever Today.” This incontinent punning and rhyming and clanging was virtually instantaneous, occurring with a speed no normal person could match. It resembled Tourettic or savantlike speed, the speed of the preconscious, undelayed by reflection.

When we arrived at the restaurant, Clive did all the license plates in the parking lot and then, elaborately, with a bow and a flourish, let Deborah enter: “Ladies first!” He looked at me with some uncertainty as I followed them to the table: “Are you joining us, too?”

When I offered him the wine list, he looked it over and exclaimed, “Good God! Australian wine! New Zealand wine! The colonies are producing something original—how exciting!” This partly indicated his retrograde amnesia—he is still in the nineteen-sixties (if he is anywhere), when Australian and New Zealand wines were almost unheard of in England. “The colonies,” however, was part of his compulsive waggery and parody.