Some might have worried that Alicia Keys, after winning five Grammys and selling 5 million copies of her remarkable 2001 debut Songs in A Minor, would pull a Lauryn Hill. (Hill, after sweeping the Grammys in 1999 with her smash solo debut The Miseducation of Lauryn Hill, disappeared from the music scene only to emerge as a shadow of her former self with 2002’s bizarre MTV Unplugged No. 2.0.) Diary, though, should lay any doubts to rest. Keys hasn’t kept fans waiting too long for her follow-up and, more important, she lives up to the staggeringly high expectations set by Songs. Like The Godfather Part II, this is the rare sequel that doesn’t disappoint. In fact, with the first single, “You Don’t Know My Name,” and “If I Ain’t Got You,” Keys has a killer one-two punch that matches Songs’ “Fallin’ ” and “A Woman’s Worth.” “You Don’t Know My Name,” with its ’60s-style street-corner harmonies and a spoken interlude during which she makes a cell-phone call to an unsuspecting crush, sounds so much like an old-school soul classic, you’ll swear it has to be a remake (it isn’t). “If I Ain’t Got You,” which showcases Keys’ raw vocal emotion and classically trained piano playing, is a stunning ballad that brings to mind vintage Aretha. It’s that good. Retro R&B influences abound throughout, from echoes of Marvin Gaye’s “Save the Children” on “Nobody Not Really” to the sizzling ’70s funk of “Heartburn” to a hip-hoppish reworking of Gladys Knight and the Pips’ 1970 hit “If I Were Your Woman.” As on Songs, Keys honors R&B’s golden age with an old soul far beyond her 23 years.