"I just feel like it's a gift, and just feel like it was such a springboard for me, as a woman," Alicia Keys tells Apple Music. "This was really my first step into womanhood. Songs in A Minor was like the tail end of my teenage years, and Diary of Alicia Keys was that first step into, who are you, what do you think, how do you feel, and what are you going through?" Keys went from teenage prodigy to 21st-century soul queen almost instantly after the release of her 2001 debut, and she continues to wear her crown with confidence on her beloved 2003 follow-up. Keys reaches back two decades for inspiration, giving special attention to R&B balladry with a smouldering cover of Gladys Knight’s “If I Was Your Woman” and invoking the lush elegance of Philly soul with “You Don’t Know My Name”. Better still: “Heartburn”, a sweat-drenched throwback to ’70s funk co-produced by hip-hop mastermind Timbaland. And Alicia displays a definite Aretha Franklin influence on “Wake Up”, a strutting number with provocative lyrics. As on her first album, Keys’ grasp of songwriting craft and classically trained piano lends these tracks uncommon substance. Her innate poise as a singer only makes the erotic longing of her lyrics all the more effective—tracks like “Karma” and “Samsonite Man” carry an especially potent charge. Instrumental interludes help frame these sonic vignettes of loneliness and desire. It all adds up to make Keys’ Diary a must-hear work. After she travelled the world touring in support of Songs in A Minor and reaping its rewards, Keys felt it was essential to get grounded before diving into making music again. "I really wanted to do my laundry, and I really wanted to shop for food," she explains. "There was something that was really just very plain and everyday about it that I needed to reconnect to. It was imperative that I did that." The Diary of Alicia Keys became a pivotal piece in Keys' discography due to the mixing of classical tones, hip-hop elements that were influenced by her favourite rappers, and the plush sounds of '70s soul balladry that wove throughout the album's 15 tracks. Notable cuts such as the Gladys Knight cover "If I Was Your Woman" were elevated by drums courtesy of producer and frequent Notorious B.I.G. collaborator Easy Mo Bee. "'If I Was Your Woman' was really fascinating, because my love for Gladys Knight had been developing over so many years," Keys says. "Because she's such a legendary, gorgeous voice and creative. But also because that mixture between that and coming back to the world of Biggie was something that I was messing with for quite a long time, trying to really figure out how to pull that all together. And when Easy Mo Bee came to me, it was like meeting a piece of [the] most important her-story." The lead single, "You Don't Know My Name"—produced by Kanye West and featuring a sample of The Main Ingredient's 1975 hit "Let Prove My Love to You"—had a new life on social media 20 years after the album's release, thanks in part to people re-enacting the dialogue of the record—which was West's idea to add. "When Ye and I got back together, that was the moment where he was like, 'What we need to do is one of the things on those ’60s records, but they start talking,'" she recalls. "We're sitting here brainstorming the whole thing." Keys holds her sophomore effort in very high regard: Diary raised her confidence, helped her connect to people and stay true to who she is as an artist. "I love this record. I love celebrating this record," she says. "I can't believe it. It is crazy. I love that this shit is still relevant."