Ann Powers's new book Good Booty takes its name from the original chorus to Little Richard's "Tutti Frutti." A passage on the title typifies the author's passionate, erudite style.

Within those two words are all the glories and contradictions raised — aroused — by American eroticism as expressed through popular music. There's the unapologetic crudeness, an openness that refuses to veil sex in niceties. There is an acknowledgement that this is also a realm of commerce and plunder, of booty earned and stolen. There is, of course, that reference to the ass, the centrifuge in a dancer's body, which can be both an exploited fetish object and a partner's cherished private pleasure. And there is the assurance that, fundamentally, the desire for the erotic is good, something that can make a person whole, make them shout and sing.

If Good Booty makes a single argument, it's that the body has always been at the center of American popular music — and that it's through that music that we've long channeled subjects that are too hard, for a variety of reasons, to put into words. In other words, American pop is about sex, but it's not just about sex: it's also about race, and gender, and class. It's where we hash out the tension between our egalitarian ideology and our stratified, segregated reality.

Another way to read the book, though, is as a series of arguments. Powers devotes a chapter to each of eight key periods in American popular music, but rather than try to encompass the totality of each period, she focuses in on sites, genres, and performers who she sees as holding the keys to understanding the era's broader zeitgeist.

The book starts, thus, with a century-spanning chapter that examines New Orleans in the 1800s. In particular, Powers considers the realities and the fantasies surrounding Congo Square, an African-American gathering space and the crucible of jazz. Next, it's off to New York in the Jazz Age, when new technologies facilitated the spread of dance fads and the resetting of social norms in an era of upheaval.

As she approaches mid-century, fans of rock music will start to really perk up. A chapter on "spiritual erotics" takes a fascinating journey through the rise of gospel music — pointing out that rockers and bluesmen like Ray Charles were able to draw on the gospel tradition for their unambiguously sexual music because gospel artists had already brought the body into their songs of praise. Here's Powers on the seminal composition by gospel great Thomas A. Dorsey.

"Take My Hand, Precious Lord" stands at a crossroads more crucial than any that hosted a devil out to take a bluesman's soul. This song, so seemingly simple, created a space where the beauty and poeticism of desire was revealed, and where the physicality of spiritual longing could be manifest.

Powers also notes the rock-star status of gospel vocal groups, whose suggestive leg-waggling lit fires in their fans' loins as well as their hearts. She goes on to trace Elvis Presley's connection to a gospel blues tradition that wasn't as segregated as some assume. He didn't necessarily "sneak" into the black church down the road...in fact, at least once he performed on the altar, as other white singers occasionally did.

Again and again, Powers delves beneath the conventional wisdom about pop and rock history. In her chapter on teens in the '50s, for example, she acknowledges the emergence of a self-conscious class of adolescents as being important to the rise of rock and roll, but she also points out that "fears about a shortage of men after World War II fed a trend toward early marriage. Girls often began dating at twelve. Parents sanctioned this by organizing middle-school dances and other 'adult' activities for their children." She sees Buddy Holly and Little Richard as embodying the ego and the id of rock and roll as popularized by Presley ("if rock and roll was a virus, Elvis was its irresistible Typhoid Mary"), and notes that Richard, at least, claims that he and his friend Buddy once shared in a threesome.

In the '60s, Powers is less interested in the Beatles and the Stones than she is in "the ultimate threesome": Jimi Hendrix, Jim Morrison, and Janis Joplin. All three, Powers argues, "tested the confines of identity with a forcefulness informed by musical restlessness and an acute awareness that at any moment they could become stuck within shrinking versions of the very archetypes they refreshed."

That restlessness grew in the 1970s. Powers devotes much of this chapter to groupies, who she describes as paradoxically being disempowered in the very act of seizing their own sexual power. For young girls (and boys) to pursue stars like Bowie and Plant and Zappa was neither new nor surprising, and Powers dwells on the poignance of the ways in which the era's norms simultaneously liberated and trapped both fans and — not to sugarcoat the very real fact of exploitation — stars, who were pressured to project an impossible ideal of virility and power.

Then came the '80s, and the AIDS era. Powers is downright poetic in her musings on Michael Jackson, the sweet boy who seemed tormented by erotic repression; Prince, who sang sexy songs about women being on top ("He looked at me like a gay woman would look at another woman," Powers quotes Wendy Melvoin as saying); and Madonna, who emerges as the perfect Reagan-era star because she was able to package sexual liberation in an accessible package that wasn't so threatening or alienating that it foreclosed mammoth commercial success. As Powers puts it, "she cleared a space where eroticism could run free."

After the rise of hip-hop and the nadir of rap-rock — a movement that, Powers, argues, embodied the most misogynistic aspects of both genres, without the liberating charge of either — comes the 21st century, which Powers describes as the era of "hungry cyborgs."

Cyborg number one? Britney Spears, who Powers describes as the perfect pop star for the dawn of the virtual-reality era. With an image as manufactured as her Swedish-engineered sound, Spears had a relentless work ethic that "was the opposite of the punk-inspired spontaneity and slack embraced by 1990s rock stars like Kurt Cobain." Powers traces a key origin of this aesthetic to Janet Jackson's iteration of the Minneapolis Sound. (There's a reason, Powers suggests, that Janet's breakout album was titled Control.)

The artist whose sound and story seem to point the way to the next phase of music and sex is, of course, Beyoncé. Powers finds the robot glove in the impeccable "Single Ladies" video to be significant, but argues that Bey's game-changing self-titled album "fought back against the assumption that to live online was to surrender any real control over one's private life. It showed how a person could reveal herself without being violated."

Powers's epilogue likens Lemonade, aptly, to "a marriage counseling session." It may be part of a new wave of albums by women artists that are works of both passion and protest, upending the status quo once again. The album argues that black lives matter, which, Powers notes, also means that black bodies matter. The same goes for women's bodies, which, of course, have been objectified far more than they've been respected in popular music. "When we think we can't move," Powers concludes, "the music is always there to say we can."