A review by Jon Caramanica for The New York Times. 

There are vocal powerhouse pop stars, who dominate with the sheer magnitude of their gift; kaleidoscopically vivid pop stars, who dazzle with enthusiasm and energy; diligent pop stars, who chip away at success until they strike oil; cheeky pop stars, who understand the absurdity of the situation but manage to convincingly stay the course.

And there is Rihanna, who is not quite any of these things.

That deficit has not proved to be much of an obstacle. More than three years have passed since the release of her last album, and she is perhaps more famous than ever, a star of fashion, social media and tabloids who sometimes, y’know, makes music or whatever.

And while she has just released “Anti” (Roc Nation), her eighth album, that peculiar state of affairs is unlikely to change. “Anti” is a chaotic and scattershot album, not the product of a committed artistic vision, or even an appealingly freeform aesthetic, but rather an amalgam of approaches, tones, styles and moods. Depending on the moment, she is an electric vocalist or an indifferent one, an emotional savant or a naif, a singer who understands what her voice is best at and one who sounds like she’s merely following directions.

Rihanna has always shined when at her most assertive, like on “Needed Me,” one of this album’s highlights. Over a pulpy, throbbing beat by DJ Mustard, Rihanna sings about using men for sex and disposing of them like tissues: “Trying to fix your inner issues with a bad bitch/Didn’t they tell you that I was a savage?” If she were sweating at all, it would come off as a scold, but her singing is reserved and cool — she’s letting a poor sap down and practically has her back turned.

She succeeds at this end of the spectrum, and also the other, like on“Work,” the single released Wednesday morning. A pop-dancehall number that’s all bubble and no depth, it’s cheaply effective. In places, she barely even relies on words, truncating her syllables past patois to something far less exact.

That Rihanna can be post-language and still thrive is among her gifts, and on “Anti,” she is relying on a range of talents rather than a fixed strategy. Around the time of her last album, “Unapologetic” (Def Jam), released near the end of 2012, Rihanna was at her creative peak, having honed a haughty, gothic, erotic sound. But the intervening years have been more curious than productive. The medium in which she’s most excelled has been Instagram — her account was gloriously unfiltered before it mysteriously disappeared. At its apex, it showed Rihanna being exceptional at being famous, a sunburst of unimpeachable cool.

Last year, she released three singles — the winning country-soul number “FourFiveSeconds,” a collaboration with Kanye West and Paul McCartney; the limp “American Oxygen”; and “Bitch Better Have My Money,” probably the most basic and least imaginative of her tough-talk hits.

But none of those songs appear on “Anti,” an album that has been long in the works and that arrives burdened by heavy expectations. The album’s rollout was troubled right down to the final step: “Anti” leaked online Wednesday evening before being officially made available for streaming. (A limited number of free downloads were given away as part of a promotional arrangement with Samsung.)

One of the many hiccups on the path to “Anti” was a recent Twitter eruption by Glass John, a writer and producer who worked on the album and suggested it was being held up because Travis Scott, the rapper who is Rihanna’s rumored boyfriend, was getting in the way. That both men’s fingerprints on this album are so clear is one indication of its patchwork approach. Mr. Scott helped produce the determinedly sloppy “Woo,” with dark, distorted production akin to his hit “Antidote.” Glass John, meanwhile, helped make “Kiss It Better,” an ostentatious sex jam that pulses with 1980s synth-rock sleaze.

“Kiss It Better” is also one of several songs on “Anti” on which Rihanna’s singing takes center stage. It’s true, too, on the three songs that close the album, each of which pulls Rihanna in an unanticipated musical direction, anchored only by her flexible voice. “Love on the Brain” is a calm doo-wop song about toxic love: “You love when I fall apart/So you can put me together/And throw me against the wall.” Then comes “Higher,” a smoldering soul number where Rihanna finds a scratchy, Amy Winehouse-esque part of her voice she’s never used before. Finally, there’s the piano ballad “Close to You,” the most affecting torch song of her career.

As songs, each of these is imperfect, but together they make an improbable argument: Rihanna may be near her vocal peak, at the place in her career where it matters the least. (This is also undoubtedly a testament to the gifts of her vocal producer, Kuk Harrell.)

But there are plenty of counterarguments here, as well: the lumpy “Desperado”; the tepid “Never Ending,” which unimaginatively borrows from Dido’s “Thank You”; and the foggy “Same Ol’ Mistakes” — a cover of Tame Impala’s “New Person, Same Old Mistakes” — a six-minute-thick moat of pseudo-chillwave bringing down this album’s middle.

That all these songs exist side by side reaffirm that Rihanna is our least aesthetically consistent — least aesthetically committed? — major pop star. At this stage of her career, music may be the least essential brick in her house. And as Rihanna has made clear time and again, not only is the sum greater than the parts, but the sum might also have nothing to do with the parts whatsoever.