Early in a Cat Stevens, a.k.a. Yusuf Islam, a.k.a. Yusuf/Cat Stevens, concert in Boston a couple of years ago, there was a hushed pause in the room as the then sixty-six-year-old performer waited for a stagehand to bring him a guitar in between songs. “I’m really happy to be here!” the singer suddenly exclaimed. It did not sound like ersatz show-biz banter; it sounded humble, childlike even, as if he himself were surprised by the emotion. It sounded like capitulation. The crowd, in response, rose to its feet en masse, producing a sound that was more than just a cheer. It was an embrace. It was an acknowledgment by artist and audience alike: Cat Stevens, a figure who, for all intents and purposes, had ceased to exist more than three decades ago, had come back.

For a long time, it has been hard to love the man once known (and now known again) as Cat Stevens. In the years since he formally retired from the popular music world, in 1978, his name has popped up in the media from time to time. He would be quoted, or seen in a video-clip interview, and it was difficult to accept the visage of the person whom he now presented himself as—to reconcile this cold, humorless, unhappy, and severe-looking man with the joyful, understanding, goofy, wise songwriter whose music we’d known and loved. For a long time, the man who’d changed his name to Yusuf Islam had completely disowned his artistic output as Cat Stevens—a confusing, dispiriting slap in the face to those it once meant a great deal to.

The man who was Cat Stevens ran Islamic schools for children, spreading the word of Allah, and acted as a spokesperson for Islam. After a while, he began making some children’s albums, but he wasn’t playing the guitar, and the music was not for his traditional fan base. In interviews, he sounded defensive and removed. Some remarks attributed to him seemed to be in line with some of the more distasteful prejudices of orthodox Islam.

Then, in 2006, came “An Other Cup,” his first album of commercial music in twenty-eight years. He’d dropped his adopted last name of Islam, and was now calling himself, simply, Yusuf. Something had shifted, certainly. How welcome it was to hear that voice with that guitar again, after all these years. Still, the album’s opening track, “Midday (Avoid City After Dark),” set a tone of unease, paranoia, and judgment that never really lifted. Elsewhere on the recording, there was a revisit to a much earlier composition (“I Think I See the Light”) and an interesting (if forced-sounding) reworking of a section of his “Foreigner Suite” (“Heaven/Where True Love Goes”), but the bulk of the album felt earthbound. Nowhere was there the joie de vivre that inhabited his best work. The follow-up, “Roadsinger,” in 2009, sounded fresher, but still unconvincing. Which was it—was he wary of us, or we of him? There seemed to be skepticism and distrust on both sides.

Some live performances began to appear here and there online. Yusuf was steadfast about not playing any old Cat Stevens material, save for a select few songs that he could justify in the context of his religious path, such as “The Wind” and “Peace Train.” He had collaborated on a musical called “Moonshadow” that featured actors singing some of his old songs and was having a run in Australia. It proved a critical and financial flop.

I paid attention to all of this because, unhip as this may be to admit, the music of Cat Stevens once meant a great deal to me. I did not grow up listening to it, per se (I was too young), but his music became the soundtrack to my adolescence when I watched “Harold and Maude” for the first time, and my world changed. I went out and got a guitar. I listened to Cat Stevens obsessively, played and sang his songs with friends, hunted down all of his albums. While it was clear that he’d lost his way artistically on later albums like “Numbers” and “Izitso,” the earlier, classic albums that he’s still known for (“Mona Bone Jakon” through “Foreigner”) were full of treasures that could be mined again and again. Indelible melodies, beautiful production, emotionally committed performances, and, most of all, a gentle wisdom, a repudiation of the status quo, a sense that we were not alone. Here was someone who was trying to make sense of life, too; he may not have had the answers, but he was looking for them, and we were encouraged to join him. Here was a friend.

Of course, I quickly learned that Cat Stevens had already ceased to be. My adolescent soul despaired, knowing that there would be no more Cat Stevens albums, no more Cat Stevens concerts. The man who had become a hero to me had long since retired from the music world.

In time, his music, too, would fade from my consciousness. As I grew and matured, so did my musical tastes and sensibilities. I might reach for a Cat Stevens album on rare occasions, to remind myself of something that I’d once treasured, sometimes surprised that a song or album held up as strongly as it did, but his music was no longer a living thing for me. I was intrigued when he came out of retirement with the two Yusuf albums, and listened to each of them a handful of times with attendant hopes and (it seemed) inevitable disappointment. It was hard to get excited about his music now. The voice was the same, but the spirit was changed, different, unwelcoming.

Nevertheless, when it was announced, in late 2014, that he was going to perform in America for the first time in thirty-eight years, I put my misgivings aside and became a teen-ager again, queueing up for tickets on the phone the morning they went on sale. I did not listen to his latest album, “Tell ‘Em I’m Gone,” nor did I look for any news about the kinds of shows that he’d been playing of late. I simply drove up to Boston to see my old hero, expectations dimmed to almost nothing. I imagined that there I would see Yusuf Islam, delivering a respectful program of his latter-day music, with perhaps one or two old favorites thrown in as crowd appeasement. I wasn’t going for Yusuf Islam. I was going to pay homage to the singer whose music had once so inspired me, for the chance to simply be in the same room with him for the first (and what I assumed would be the last) time.

It has taken some time for me to think clearly about what it was like to be at that show. What happened there was more than just a good concert given by a group of well-rehearsed, talented musicians, backing a pop icon on a comeback tour, though it was partly that. It was more than just a nostalgic trip down memory lane, as a sold-out crowd sang along to songs that many (including myself) never expected to hear played live again, though it was partly that, too. Without resorting to hyperbole, being there, for me, was an unexpected catharsis, something like seeing a ghost.

I didn’t know, until I got there, that the singer was now billing himself with the ungainly but revealing name of Yusuf/Cat Stevens. Was he now acknowledging his former self? This was a surprise, the first of many that the evening would hold.

The once and future Cat Stevens walked onstage to a tremendous ovation (no surprise there) and launched into a solo performance of “The Wind.” O.K., in some way, this was what we’d all come for, and here he’d already given it to us. All the latter-day Yusuf stuff would follow, we’d give him some hearty applause at the encore, and that would be that—or so I thought. What was this, though? He was wearing sunglasses and a leather jacket—not the austere, devotional garb he’d worn in the (admittedly not so recent) appearances that I’d seen online. And the stage set—it was elaborate, whimsical, evocative of the old Cat, whose tastes sometimes crossed the line into outright silliness. Most significantly, though, he himself seemed engaged, connected, and—hardest to believe—lighthearted.