Anybody seeking an exhaustive Britney Spears compilation has been waiting for a collection like 2013's The Essential Britney Spears. Where other Britney compilations ran no longer than a single CD, this is a double-disc set with over 30 tracks more than enough space for all of her hit American singles, although that does mean that there are some singles from non-U.S. territories that are missing in action.

Like 2004's Greatest Hits: My Prerogative, 2009's The Singles runs 18 tracks but the selected songs result in a very different listening experience. To begin with, the five years separating the two compilations were tumultuous ones for Britney Spears, but they resulted in a clutch of hits that kept her on the charts despite all the drama, hits that firmly entrenched Britney as a dance club diva. This stretch of six singles – "Gimme More," "Piece of Me," "Womanizer," "Circus," "If You Seek Amy," "Radar" – along with the excellent new Max Martin-written and produced single "3" (much better than any of the three new cuts on My Prerogative), help push The Singles away from teen pop and toward pure dance-pop bliss, a shift in tone underscored by the virtual absence of ballads (the only one included is "Everytime," which in this context plays a bit as a chill-out number). In some regards, giving her early sticky bubblegum and fluffy ballads a bit of a short shrift does downplay Britney's era of dominance, but it does result in a stronger overall listen, since there are no slow patches here, just a parade of relentless hooks and rhythms that wound up defining the sound of a decade.

Britney Jean is Britney Spears' eighth studio album and was released in late fall 2013. The album has been described by Spears as the most personal record from her catalog yet, and features collaborations with numerous producers including Sia Furler, will.i.am, William Orbit, and Naughty Boy. Spears co-wrote each track on the album, which is a concept album about the loneliness of pop life. Two singles have been released thus far, "Work Bitch" and "Perfume".

The soft commercial performance of 2013's Britney Jean made it clear that it was time for Britney Spears to shake up her recording career – a move made somewhat less urgent due to the success of Britney: Piece of Me, the residency show she launched at Las Vegas' Planet Hollywood a few months after the release of Britney Jean. Sin City's influence can be heard within the splashiness of the arrangements of certain portions of Glory, the 2016 album designed to be Britney's return to the Top 40. To that end, Glory downplays the show biz glitz of Vegas in favor of modern dance-pop, one with EDM undercurrents and hip-hop overtones.

On her ninth album, Britney Spears sounds happy to have settled into her status as a grande dame of forward-thinking pop. Downtempo offerings like the gauzy come-on “Make Me…”, the reggae-inflected Tinashe duet “Slumber Party” and the cooing “Man On the Moon” put Spears’ sensual side on full display. On the wide-eyed, bouncy “Clumsy”, the swaggering “Do You Wanna Come Over?” and the vampy “What You Need”, she gets playful over booming beats. This expanded deluxe edition includes fresh remixes of “Mood Ring” and the brand-new single “Matches”, a glossy collaboration with the Backstreet Boys that feels like a long-time dream come true for early-aughts pop fanatics.