LONDON — “I’m not going to cry,” Adele said. She was practicing with her band at Music Bank rehearsal studios, an unglamorous warehouse space in South London, and had just finished “When We Were Young,” one of the torchiest ballads on her new album, “25.” It’s a song about running into an old flame that confesses, “I still care” and then, tentatively, asks, “Do you still care?”  Adele can get caught up in her own songs, and she wouldn’t want to change that. “In order for me to feel confident with one of my songs it has to really move me,” she said. “That’s how I know that I’ve written a good song for myself — it’s when I start crying. It’s when I just break out in [expletive] tears in the vocal booth or in the studio, and I’ll need a moment to myself.”  That heart-on-sleeve emotion, conveyed by a gorgeous voice, has made Adele, now 27, one of the most universally beloved singers and songwriters of the 21st century. Adele, whose last name is Adkins, won the Grammy as Best New Artist with her 2008 debut album, “19.” She multiplied her audience with “21,” her 2011 album full of breakup songs — angry, regretful, lonely, righteous — that used modern production touches around vocals filled with old-fashioned soul. It has sold 30 million albums worldwide, 11 million in the United States. Beyond the power of Adele’s voice and the craftsmanship of the music, “21” communicated a palpable sincerity and urgency, the feeling that its wounds were still fresh.  “She’s got this incredible intuition about what’s right and what’s real and what suits her,” said Paul Epworth, who wrote and produced songs with Adele on both “21” and the new album. “She’s the sharpest, most instinctive artist I’ve ever worked with. She’s pure gut, pure intuition.”  The question that loomed over Adele in her four years between albums was how — or if — she could follow her blockbuster with something equally striking. “There is no beating or redoing ‘21,’” said Ryan Tedder, another producer and songwriting collaborator for both “21” and “25.” “You’re lucky if at one point in your life you stumble across a unicorn in the woods. The odds that you find a second unicorn are extremely remote, and she’s aware of that. I think that ‘25’ will be enormous, regardless of anything. But that wasn’t the goal. She wanted to put out the best thing that was the most honest.”  At this rehearsal, with a journalist in the room, Adele was a musician above all. She moved decisively through new songs and old ones in preparation for TV appearances and a Radio City Music Hall concert (and NBC TV taping) on Tuesday, Nov. 17, three days before the worldwide release of “25” (XL/Columbia). And she sang in full-throated glory, capturing the vengeful bite of past hits like “Rolling in the Deep” and the hushed suspense and pealing chorus of her new one, “Hello.” Her stage arrangements echo her albums; she wants the songs familiar enough for fans to sing along.  Adele had largely maintained public silence while recording “25.” Her reticent re-emergence was a brief, anonymous television advertisement, first shown on Oct. 18 during “The X Factor” in Britain. It was the beginning of “Hello”: just somber piano chords, Adele’s voice and the lyrics — “Hello, it’s me/I was wondering if after all these years you’d like to meet” — with no other information.  Unlike most other pop hitmakers her age, Adele barely uses social media. It’s one of the many charmingly old-fashioned aspects of her career. But she does have a Twitter account, and she couldn’t resist looking online to see if her voice had been recognized. When she did, she saw only three tweets.  She panicked. “I was like, ‘Oh, no, I’ve missed my window,’” Adele said over a cup of tea a few days after the ad. “‘Oh, no, it’s too late. The comeback’s gone. No one cares.’”  But then, she recalled, her boyfriend, Simon Konecki, joined her at the computer and showed her that thousands of other tweets were pouring in. Once “Hello” was released on Oct. 23, more than 1.1 million people bought the song as a download in its first week in the United States alone, and tens of millions streamed the audio and watched the video clip.  “Hello” doesn’t just introduce “25”; in many ways, it sums up the album. On “25,” the rage and heartache of “21” are replaced by longing: for connection, for youth, for reconciliation and for lifelong bonds. Like other songs on the album, “Hello” is filled with thoughts of distance and the irrevocable passage of time, of apologies and coming to terms with the past. Musically, “Hello” has verses with just voice and piano followed by huge, ringing choruses; similarly, the album as a whole switches between organic, unplugged ballads and booming modern pop.  As she wrote the album, Adele was no longer the heartbroken avenger she had been on “21”; she had become an internationally recognized star and, at 23, a mother. In October 2012, she had a son, Angelo, with Mr. Konecki. She collaborated on writing “Skyfall,” the James Bond movie theme that would bring her an Oscar, while she was pregnant. Tattooed along her right pinky is “Angelo”; on her left pinky is “Paradise” because, she explained, “He’s my paradise.”  Adele took time to raise her infant as she pondered what to do next. “I was scared,” she admitted. “It got so out of control, the last album. I was a bit frightened for a while to step back into it.” Health problems, including a vocal hemorrhage that threatened to permanently damage her voice, had forced her to cancel extensive touring in 2011 and undergo throat surgery; regardless, “21” was a bulwark of the recorded music business throughout 2012. With “25,” she said, “I won’t do less touring than I did before, but what I did before wasn’t that much.”  Adele made her first efforts to write new songs in 2013. Initially, she said, “I didn’t think I had it in me to write another record. I didn’t know if I should. Because of how successful ‘21’ was, I thought, ‘Maybe everyone’s happy with that being the last thing from me. Maybe I should bow out on a high.’”  Of course, she changed her mind. “As time went on, I realized I had no choice,” she continued. “I have to write more music for myself, and there’s nothing else I want to do.”  In an interview before rehearsal, Adele was nestled in a black leather armchair at Soho House Dean Street, an antique-filled Georgian townhouse, in a sitting room reserved by her manager to assure privacy. As Adele’s concert audiences have learned, she’s a voluble, unguarded talker, more willing to confess insecurity or ponder her duty to her fans than to promote herself. She doesn’t hide her unposh North London accent, and she cheerfully flings profanities and breaks into her melodic bark of a laugh.  She was wearing a voluminous dark-blue sweater, black Converse high tops and a pair of baggy black pants that, she admitted, were actually pajama bottoms. I joshed that she might start a trend in Britain. “It already is a bit of one,” she said, and laughed. “But for skinny people.”  Adele would not revisit the making of “21” even if she could. “I just used to let myself drown,” she said. “If I was sad, if I was confused — which I would say were the running themes for most of my records so far — I’d just go with it. I’d let myself fall apart, and I’d sit in darkness, and I’d feel sorry for myself, and I wouldn’t accept any help to get out of it, in terms of going out with my friends to cheer me up, or staying busier. No! I loved the drama of it all.”  She added: “How I felt when I wrote ‘21,’ I wouldn’t want to feel again. It was horrible. I was miserable, I was lonely, I was sad, I was angry, I was bitter. I thought I was going to be single for the rest of my life. I thought I was never going to love again. It’s not worth it.”  She reconsidered for a moment. “Well, it was worth it, because, obviously, of what’s gone on. But I’m not willing to feel like that to write a song again. I’m not.”  Now that she’s a parent, “I haven’t got time to fall apart,” she added. “I’m the backbone for my kid, and I want to be there for him. And I want to be there for my boyfriend as well, and I don’t want to bring them down with me for my art.”  Although she emerged to perform “Skyfall” at the 2013 Academy Awards, Adele devoted much of her time between albums to “the most normal things you could ever imagine,” she said. “I’ve been to every park, every museum, every shopping center.”  Determined to be known for music and music only, Adele also turned down endorsements and cross-marketing projects that would have kept her highly visible. “If I wanted to just be famous, like be a celebrity, then I wouldn’t do music, because everything else I’ve been offered would probably make me more famous than I am just with my music,” she said. “Commercials, being the face of brands, nail varnishes, shoes, bags, fashion lines, beauty ranges, hair products, being in movies, being the face of a car, designing watches, food ranges, buildings, airlines, book deals. I’ve been offered everything. And I don’t want to water myself down. I want to do one thing. I want to make something. I don’t want to be the face of anything.  “Everyone thinks I just disappeared, and I didn’t,” she said. “I just went back to real life, because I had to write an album about real life, because otherwise how can you be relatable? If I wrote about being famous — that’s [expletive] boring.”  When she tried to start the new album in 2013, Adele came up empty. “I didn’t have a subject,” she said. She was reluctant to write about her son. “He’s the love of my life and the light of my life, but he’s no one else’s apart from me and his dad. So no one else can really relate to that. Also, all my fans aren’t parents, so they wouldn’t want to listen to that.”  Yet it was a maternal love song, “Remedy,” that restored Adele’s confidence, she said, and was the turning point for “25.” Mr. Tedder had the word “remedy,” some waltzing piano motifs and the idea that the song might be about someone beloved; he looked to Adele for the rest. “She immediately said, ‘This is about my kid,’” Mr. Tedder recalled. “That unlocked the whole lyric. And it was done, written and recorded that day.”  Adele worked with her previous producers, like Mr. Tedder and Mr. Epworth, and with new collaborators from pop’s top echelons: Sia; Bruno Mars; and the producers Greg Kurstin (Pink, Sia, Kelly Clarkson), Max Martin (Taylor Swift, the Weeknd) and Danger Mouse (Gnarls Barkley, the Black Keys).  She was resolved not to repeat “21”; she also, for the first time, discarded as many songs as she kept. “The girl has probably thrown away easily 20 hits off of ‘25’ that will at some point wander away, maybe into other artists’ hands,” Mr. Tedder said. “With Adele, it’s not about ‘Can I get a hit? Can I sing that note? Can I get with the best producers?’ It’s about, ‘What’s the story?’”  The story, in many songs on “25,” is about what to hold on to from the past and what to let go. The songs plunge into their own fears and uncertainty. “Million Years Ago,” a delicate guitar ballad with a hint of Edith Piaf, mourns lost youth and confesses, “I feel like my life is flashing by/And all I can do is watch and cry.”  At rehearsal, Adele sang “Million Years Ago” in two versions, one beginning a cappella with her voice completely alone and exposed. There were tears in that voice but not, for the moment, in her eyes.  A version of this article appears in print on November 15, 2015, on page AR1 of the New York edition with the headline: Tracks of Her Tears. Order Reprints| Today's Paper|Subscribe
The British singer discusses the challenge of following up the success of “21,” how motherhood has changed her and why she avoids being a celebrity.