FIFTH GRADE.

For people under thirty, Eminem may be the most significant recording artist in the English-speaking world. His previous album, "The Eminem Show," sold eight million copies in a little under a year. (The Beastie Boys' "Licensed to Ill," an equally politically incorrect though vastly superior record by equally white rappers, took twelve years to sell that many copies.) Eminem's new album, "Encore," has sold more than a million and a half copies in less than two weeks. And, terminally unpleasant or not, Eminem is occasionally astonishing, able to upend expectations and redeem his many tedious attempts to epater all of us.

Perhaps aware that shock inevitably produces its own tedium, Eminem talks in the current issue of Rolling Stone about his eight-year-old daughter, Hailie, and the difficulty of co-parenting her with his ex-wife, Kim Mathers, who has attempted suicide and was jailed earlier this year for drug possession. The article includes a discussion of Eminem's new sense of maturity.

Little of this offstage thoughtfulness can be found in "Encore" 's seventy-seven minutes of superstar petulance, bathroom jokes, misogynism, and simple lazy-assedness. Because Eminem's songs are rooted in adolescent anger and its paper-thin rationalizations, they must deliver big to justify an essentially annoying world view, either with aesthetic fireworks or with a performance convincing enough to distract us from the artist's bottomless ability to feel sorry for himself. He has done it in the past with "Lose Yourself" and "Stan," close-to-perfect songs that help explain his critical lionization.

One of Eminem's best songs was his 1997 debut single, "My Name Is," produced by his mentor and sponsor, Dr. Dre. The electric-piano sample is deceptively cheerful, just the right camouflage for an unknown white rapper from Detroit gleefully tipping over sacred cows in this confident, deadpan whine. Why did he want to impregnate pop stars and hang himself and insult his mother? At first, we didn't need to know. His rhymes were organic pieces of a perfectly pitched, if amoral, comedy. Eminem was smart enough to smile when complaining, a balance some songwriters never learn. For instance, when he was discussing the challenges of new fame, on 1999's "The Real Slim Shady," the beats and the words collided in a happily constrained way, like marbles being shaken in a jar. He had developed his own style, creating unusually long concatenations by inserting different words into the same rhythmic pattern over and over. (In the wrong hands, this method mimics a child's repetitive "Mom? Mom? Mom?") When Eminem's rhymes click, they feel both musically calibrated and lexically tuned, the careful work of someone who loves language and has crumpled up a lot of paper trying to figure out how, and where, words fit together.

But on "The Eminem Show," his third major-label album, Eminem's scansion was being squashed by his personality. No longer the underdog, he sounded like Al Pacino in "Scarface," paranoid and entitled. The humor had curdled. Eminem no longer wanted to hang himself; it was you and everyone else he was after. The beats became slow and flat, losing syncopation as the air left the room.

On "Encore," his fourth album, the rhythms have hardened into a martial clomp that leaves plenty of room for Eminem's voice but does little to help him. There's a lack of suppleness in the backing music, and that's a problem if your approach to rhyming is "and and and." His current take on "themes" doesn't help, either. "Ass Like That" is one of many icky songs, a train wreck of failed sketch comedy. Eminem raps in what may be a South Asian accent, or possibly an imitation of Triumph the Insult Comic Dog. There is a chance that he is simply making fun of non-Americans who get pulled over by the police. Before any of this becomes clear, or funny, we get an illogical chorus about impressive butts and a sitar phrase tied to a fifth-grade discussion of ...