The Queen.(Beyonce Knowles in today's music industry)

Bruce Springsteen is the de-facto governor of New Jersey, and if America were Europe Aretha Franklin would have a duchy, so both obviously belonged at the joyous Obamathon. But what about Beyonce Knowles, the twenty-seven-year-old who was chosen to sing for Obama at two inaugural events?

The world met Beyonce in 1998 as the leader of Destiny's Child, a girl group conceived in part and managed by Matthew Knowles, her father. Destiny's Child was high-tech declarations of autonomy and flair: "No, No, No," "Bills, Bills, Bills," "Independent Women, Pt. 1," and "Survivor." To underestimate Knowles and her rotating cast of backup singers is to find yourself on the business end of a No. 1 song. (Destiny's Child is the most successful female R. & B. group in history.) Yet none of this involved Beyonce cursing, committing infidelity, or breaking any laws, even in character. The Knowles empire is delicately balanced on one of the thinnest-known edges in pop feminism: as unbiddable as Beyonce gets, she never risks arrant aggression; and as much of hip-hop's confidence and sound as she borrows, she never drifts to the back of the classroom. She is pop's A student, and it has done her a world of commercial good.

She is also a strange and brilliant musician. Young black female singers rarely get past the red rope and into the Genius Lounge--the moody, the male, and the dead crowd that room. But with or without co-writers, Knowles does remarkable things with tone and harmony. The one time I met her, backstage at a Destiny's Child concert in Peoria in 2000, she talked about listening to Miles Davis and Fela Kuti--affinities I didn't know how to process until I heard "Apple Pie a la Mode," from the following year's Destiny's Child album, "Survivor." It's a slinky song, something of a throwaway, except that Prince or D'Angelo could easily have done the throwing away. Who else in the stratosphere of R. & B. pop plays around with the conversational voice like Beyonce? Who feels comfortable with adding so much unexpected, generous harmony to a trifle about a delicious crush? Anyone else with "Apple Pie a la Mode" in the bag would flip over backward, buy a retro-glam outfit, and construct an entire side project around it. Knowles simply kept moving.

Where she was heading, as she and her father must have always known, was toward a gigantic solo career. That meant that she would have to choose among unity of purpose (the way Celine Dion chose the power ballad as her sidearm of choice), full-on idiosyncrasy (as Bjork did, after leaving the Sugarcubes for a life of dedicated unpredictability), or some compromise between the two that could retain old fans while convincing tourists that she was worth following. Executed successfully, this move is called the Sting (who never matched the songwriting quality of his old band the Police but has provided himself with a robust living and a large, loyal following). Done wrong, it's called--well, many names, all of which involve repeated pleas for the old band to regroup.

Beyonce has yet to come to a decision, though her success as a solo artist seems to be entirely secure. (She has made three solo albums, all of them yielding No. 1 songs.) This is a testament to something deeply appealing about Beyonce, because her first album, "Dangerously in Love" (2003), has three good songs, at best; her second, "B'Day" (2006), is completely enjoyable; and her new one, "I Am . . . Sasha Fierce" (featuring a supposedly new, wilder alter ego), is something of a mess. Apparently, Knowles felt that it was high time to offer a ...