Because Pozner isn’t really interested in viewers, she doesn’t have much to say about why they reject some reality shows while embracing others. And she doesn’t distinguish among passing fads, like “Joe Millionaire” (which lost eighty per cent of its audience between its first season finale and its second—also its last); hardy perennials, like “The Bachelor”; and obscurities, like “When Women Rule the World” (which was scrapped by Fox months in advance of its scheduled premiere, though the series was eventually broadcast in the U.K.). She isn’t really interested in the shows’ participants, either, and, despite her attempts to shield them, sometimes they become collateral damage in her assaults on greedy executives. “Producers build on our derision by carefully casting women who are, let’s just say, in no danger of being recruited to join Mensa,” she writes. This judgment, at least, has the virtue of clarity: producers are bad, though probably smart; participants are dumb, though possibly good.

Viewers wanting a subtler verdict should seek out “Makeover TV: Selfhood, Citizenship, and Celebrity” (Duke; $23.95), Brenda R. Weber’s strange and thoughtful survey of makeover shows. Defined loosely, this category, built around twinned narratives of physical and spiritual transformation, includes a wide range of reality programming: not only “The Swan” and “What Not to Wear” but also “Dog Whisperer,” which tames rowdy pets; “The Biggest Loser,” a weight-loss competition; and “American Idol,” which is, after all, about the transformation of amateurs into pop stars. (Even “The Real World” is, in some sense, a makeover show, precisely because of its artificiality: having been thrown together in a strange house with strange people, the participants generally assume that the experience will be educational, or even therapeutic.) Weber, a professor of gender studies at Indiana University, takes care to avoid snap judgments. Her approach is informed by the work of the feminist scholar Kathy Davis, who has rejected the idea that cosmetic surgery and other aesthetic interventions are inherently or purely oppressive. Weber quotes one of Davis’s insights with approval: “Women are not merely the victims of the terrors visited upon them by the beauty system. On the contrary, they partake in its delights as well.” The thought of women renovating their wardrobes or their faces inspires in Weber not horror but a tantalizing question: “Why shouldn’t the painful vestiges of class and circumstance that write themselves on the body be not only overwritten but erased altogether?”

Weber sees in these makeover programs a strange new world—or, more accurately, a strange new nation, one where citizenship is available only to those who have made the transition “from Before to After.” Weber notices that, on scripted television, makeovers are usually revealed to be temporary or unnecessary: “characters often learn that though a makeover is nice, they were really just fine in their Before states.” On reality television, by contrast, makeovers are urgent and permanent; “the After-body, narratively speaking, stands as the moment of greatest authenticity.” We have moved from the regressive logic of the sitcom, in which nothing really happens, to the recursive logic of the police procedural, in which the same thing keeps happening—the same detectives, solving and re-solving the same crimes. In fact, Weber points out that a number of makeover shows present their subjects as crimes to be solved: in the British version of “What Not to Wear,” makeover candidates line up in front of a one-way mirror, like perpetrators awaiting identification; “Style by Jury,” a Canadian show, begins and ends with the target facing a jury of her peers.

Makeover shows inevitably build to a spectacular moment when “reveal” becomes a noun, and yet the final product is often unremarkable: a woman with an up-to-date generic haircut, wearing a jacket that fits well; a man who is chubby but not obese; a dog with no overwhelming urge to bare its fangs. The new subject is worth looking at only because we know where it came from, which means that, despite the seeming decisiveness of the transformation, the old subject never truly disappears. “The After highlights the dreadfulness of the Before,” Weber writes. “In makeover logic, no post-made-over body can ever be considered separate from its pre-made-over form.” She might have added that no makeover is ever really finished; there is no After who is not, in other respects, a Before—maybe your dog no longer strains at the leash, but are you sure that sweater doesn’t make you look old and tired? Are you sure your thighs wouldn’t benefit from some blunt cannulation? Weber’s makeover nation is an eerie place, because no one fully belongs there, and, deep down, everyone knows it.

The transformation, however partial, of a Before into an After usually requires accomplices, who may go through their own transformation during the show, “from cranky witches to good friends to benevolent fairy godmothers (or superheroes),” as Weber puts it. Often, these accomplices, like their fairy-tale counterparts, live outside the social worlds of the people they help. “Queer Eye for the Straight Guy,” which began its run in 2003, epitomized this tendency: the title implied (and the show seemed to confirm) that the makeover targets needed a kind of help that no member of their tribe—the “straight guy” tribe—could provide. Weber argues that the “Queer Eye” experts, like other gay makeover agents, “function as a foil against which to read the emerging hegemonic masculinity of the made-over man.” But, surely, their marked difference is often related to the authority they project. (Think of Simon Cowell, for years the toughest “American Idol” judge: his British accent and his status as a lifelong non-singer made his judgments seem all the more definitive.) “Mostly male doctors on plastic surgery shows are relentless about the horrors of looking masculine,” Weber writes, and yet some of the same doctors who upbraid “masculine” women playfully defy gender norms: Robert Rey, the celebrity-obsessed star of “Dr. 90210,” is known for his smooth skin, and for the sleeveless scrub shirts he prefers, many of which are equipped with plunging V-necks, the better to display his pectoral cleavage.

Sometimes these agents of change seem purposely to sabotage their own messages. In her book, Pozner reserves special condemnation for “Charm School,” the VH1 program that purported to offer social rehabilitation to ill-mannered dating-show veterans; she protests that the “smug, white, wealthy ‘dean,’ Keith Lewis”—a modelling agent and pageant judge—“offered only condescension.” Weber, more astutely, argues that arbiters like Lewis function effectively as parodies of authority: “the lessons are so shallow, the uptight behavior of the experts so much less engaging than the ebullience of the subjects, that these ‘learn to be proper’ shows in many ways rebuke the very transformations they portray.” A show like “Charm School” is, at heart, an expression of the audience’s strong but mixed feelings about makeovers in general: we like the idea of melioration, but how much change do we really want? Weber returns to this question at the end of her book, when, in an autobiographical turn, she describes a visit to an orthodontist, who offers to straighten her teeth for five thousand dollars. She declines, but finds herself tempted—and she can’t help but notice that the orthodontist might benefit from otoplasty to pin back his ears. And so she returns, implicitly, to the question of whether the body’s “painful vestiges of class and circumstance” can be overwritten or erased. The answer is yes—but not for free and not for good.

Jay-Z explains not only what his lyrics mean but how they sound, even how they feel:

When a rapper jumps on a beat, he adds his own rhythm. Sometimes you stay in the pocket of the beat and just let the rhymes land on the square so that the beat and flow become one. But sometimes the flow chops up the beat, breaks the beat into smaller units, forces in multiple syllables and repeated sounds and internal rhymes, or hangs a drunken leg over the last bap and keeps going, sneaks out of that bitch.

Two paragraphs later, he’s back to talking about selling crack cocaine in Brooklyn. His description, and his music, makes it easier to imagine a connection—a rhyme, maybe—between these two forms of navigation, beat and street. And, no less than Bradley and DuBois, Jay-Z is eager to win for hip-hop a particular kind of respect. He states his case using almost the same words Bradley did: he wants to show that “hip-hop lyrics—not just my lyrics, but those of every great MC—are poetry if you look at them closely enough.”

If you start in the recent past and work backward, the history of hip-hop spreads out in every direction: toward the Last Poets and Gil Scott-Heron, who declaimed poems over beats and grooves in the early seventies; toward Jamaica, where U-Roy pioneered the art of chatting and toasting over reggae records; toward the fifties radio d.j.s who used rhyming patter to seal spaces between songs; toward jazz and jive and the talking blues; toward preachers and politicians and street-corner bullshitters. In “Book of Rhymes,” Bradley argues convincingly that something changed in the late nineteen-seventies, in the Bronx, when the earliest rappers (some of whom were also d.j.s) discovered the value of rhyming in time. “Words started bending to the beat,” as Bradley puts it; by submitting to rhythm, paradoxically, rappers came to sound more authoritative than the free-form poets, toasters, chatters, patterers, and jokers who came before.

The earliest lyrics in the anthology establish the rhyme pattern that many casual listeners still associate with hip-hop. Each four-beat line ended with a rhyme, heavily emphasized, and each verse was a series of couplets, not always thematically or sonically related to each other:

I’m Melle Mel and I rock so well
From the World Trade to the depths of hell.

Those lines were recorded in December, 1978, at a performance by Grandmaster Flash and the Furious Five at the Audubon Ballroom, on Broadway and 165th Street (the same hall where Malcolm X was assassinated, thirteen years earlier). The springy exuberance of Melle Mel’s voice matched the elastic funk of the disco records that many early rappers used as their backing tracks.

The rise of Run-D.M.C., in the early nineteen-eighties, helped change that: the group’s two rappers, Run and D.M.C., performed in jeans and sneakers, and they realized that hip-hop could be entertaining without being cheerful. They delivered even goofy lyrics with staccato aggression, which is one reason that they appealed to the young Jay-Z—they reminded him of guys he knew. In “Decoded,” he quotes a couple of lines by Run:

Cool chief rocker, I don’t drink vodka
But keep a bag of cheeba inside my locker

There is aggression in the phrasing: the first line starts sharply, with a stressed syllable, instead of easing into the beat with an unstressed one. “The words themselves don’t mean much, but he snaps those clipped syllables out like drumbeats, bap bap bapbap,” Jay-Z writes. “If you listened to that joint and came away thinking it was a simple rhyme about holding weed in a gym locker, you’d be reading it wrong: The point of those bars is to bang out a rhythmic idea.”

The first Run-D.M.C. album arrived in 1984, but within a few years the group’s sparse lyrical style came to seem old-fashioned; a generation of rappers had arrived with a trickier sense of swing. Hip-hop historians call this period the Golden Age (Bradley and DuBois date it from 1985 to 1992), and it produced the kinds of lyrical shifts that are easy to spot in print: extended similes and ambitious use of symbolism; an increased attention to character and ideology; unpredictable internal rhyme schemes; enjambment and uneven line lengths. This last innovation may have been designed to delight anthologizers and frustrate them, too, because it makes hip-hop hard to render in print. Bradley and DuBois claim, with ill-advised certainty, to have solved the problem of line breaks: “one musical bar is equal to one line of verse.” But, in fact, most of their lines start before the downbeat, somewhere (it’s not clear how they decided) between the fourth beat of one bar and the first beat of the next one. Here they are quoting Big Daddy Kane, one of the genre’s first great enjambers, in a tightly coiled passage from his 1987 single, “Raw”:

I’ll damage ya, I’m not an amateur but a professional
Unquestionable, without doubt superb
So full of action, my name should be a verb.

These three lines contain three separate rhyming pairs, and a different anthologist might turn this extract into six lines of varying length. If Bradley and DuBois followed their own rule, they would break mid-word—“professio-/nal”—because the final syllable actually arrives, startlingly, on the next line’s downbeat. In “Book of Rhymes,” Bradley argued that “every rap song is a poem waiting to be performed,” but the anthology’s trouble with line breaks (not to mention punctuation) reminds readers that hip-hop is an oral tradition with no well-established written form. By presenting themselves as mere archivists, Bradley and DuBois underestimate their own importance: a book of hip-hop lyrics is necessarily a work of translation.

As the Golden Age ended, hip-hop’s formal revolution was giving way to a narrative revolution. So-called gangsta rappers downplayed wordplay (without, of course, forswearing it) so they could immerse listeners in their first-person stories of bad guys and good times. Shakur and the Notorious B.I.G. created two of the genre’s most fully realized personae; when they were murdered, in 1996 and 1997, respectively, their deaths became part of their stories. (Both crimes remain unsolved.) As the anthologizers blast through the nineties (“Rap Goes Mainstream”) and the aughts (“New Millennium Rap”), their excitement starts to wane. They assert that the increasing popularity of hip-hop presented a risk of “homogenization and stagnation,” without pausing to explain why this should be true (doesn’t novelty sell?), if indeed it was. There is little overt criticism, but some rappers get fulsome praise—“socially conscious” is one of Bradley and DuBois’s highest compliments—while others get passive-aggressive reprimands (“Disagreement remains over whether Lil’ Kim has been good or bad for the image of women in hip-hop”). Perhaps the form of their project dictates its content. They are sympathetic to rappers whose lyrics survive the transition to the printed page; the verbose parables and history lessons of Talib Kweli, for instance, make his name “synonymous with depth and excellence,” in their estimation. But they offer a more measured assessment of Lil Wayne, praising his “play of sound” (his froggy, bluesy voice is one of the genre’s greatest instruments) while entertaining the unattributed accusation that he may be merely “a gimmick rapper.” Any anthology requires judgments of taste, and this one might have been more engaging if it admitted as much.

Jay-Z grew up absorbing many of the rhymes that Bradley and DuBois celebrate. He was born in 1969, and raised in the Marcy Houses, in an area of Brooklyn from which Times Square seemed to be “a plane ride away.” (Nowadays, some real-estate agents doubtless consider it part of greater Williamsburg.) “It was the seventies,” he writes, “and heroin was still heavy in the hood, so we would dare one another to push a leaning nodder off a bench the way kids on farms tip sleeping cows.” He was a skinny, watchful boy with a knack for rhyming but no great interest in the music industry, despite some early brushes with fame—he briefly served as Big Daddy Kane’s hype man. Besides, Jay-Z had a day job that was both more dangerous and more reliable: he says he spent much of the late eighties and early nineties selling crack in Brooklyn and New Jersey and down the Eastern Seaboard. He was no kingpin, but he says he was a fairly accomplished mid-level dealer, and though he hated standing outside all day, he found that he didn’t hate the routine. “It was an adventure,” he says. “I got to hang out on the block with my crew, talking, cracking jokes. You know how people in office jobs talk at the watercooler? This job was almost all watercooler.” Then, almost as an afterthought, “But when you weren’t having fun, it was hell.”

Early recordings of Jay-Z reveal a nimble but mild-mannered virtuoso, delivering rat-a-tat syllables (he liked to rap in double-time triplets, delivering six syllables per beat) that often amounted to etudes rather than songs. But by 1996, when he released his debut album, “Reasonable Doubt,” on a local independent label, he had slowed down and settled into a style—and, more important, settled into character. The album won him underground acclaim and a record deal with the very above-ground hip-hop label Def Jam, which helped him become one of the genre’s most dependable hitmakers. He was a cool-blooded hustler, describing a risky life in conversational verses that hid their poetic devices, disparaging the art of rapping even while perfecting it:

Who wanna bet us that we don’t touch lettuce, stack
cheddars forever, live treacherous, all the et ceteras.
To the death of us, me and my confidants, we
shine. You feel the ambiance—y’all niggas just rhyme.

Too often, hip-hop’s embrace of crime narratives has been portrayed as a flaw or a mistake, a regrettable detour from the overtly ideological rhymes of groups like Public Enemy. But in Jay-Z’s view Public Enemy is an anomaly. “You rarely become Chuck D when you’re listening to Public Enemy,” he writes. “It’s more like watching a really, really lively speech.” By contrast, his tales of hustling were generous, because they made it easy for fans to imagine that they were part of the action. “I don’t think any listeners think I’m threatening them,” he writes. “I think they’re singing along with me, threatening someone else. They’re thinking, Yeah, I’m coming for you. And they might apply it to anything, to taking their next math test or straightening out that chick talking outta pocket in the next cubicle.”

Throughout “Decoded,” Jay-Z offers readers a large dose of hermeneutics and a small dose of biography, in keeping with his deserved reputation for brilliance and chilliness. His footnotes are full of pleasingly small-scale exultations (“I like the internal rhymes here”) and technical explanations (“The shift in slang—from talking about guns as tools to break things to talking about shooting as blazing—matches the shift in tone”); at one point, he pauses to quote a passage from “Book of Rhymes” in which Bradley praises his use of homonyms. Readers curious about his life will learn something about his father, who abandoned the family when Jay-Z was twelve; a little bit about Bono, who is now one of Jay-Z’s many A-list friends; and nothing at all about the time when, as a boy, Jay-Z shot his older brother in the shoulder. (Apparently, there was a dispute over an item of jewelry, possibly a ring, although Jay-Z once told Oprah Winfrey that, at the time, his brother was “dealing with a lot of demons.”)

“Decoded” is a prestige project—it will be followed, inevitably, by a rash of imitations from rappers who realize that the self-penned coffee-table book has replaced the Lamborghini Murcielago as hip-hop’s ultimate status symbol.