One theory for Prince’s invincibility in the ‘80s and relative fallibility in subsequent decades is that after becoming a star, he needed the Revolution to keep him in check. That notion is complicated by his masterpiece Sign O’ the Times, his first album after dismantling that backing band in October 1986.

Released 30 years ago today (March 31, 1987), Sign O’ the Times was born from Crystal Ball, a proposed triple album that Warner Bros. refused to put out. That aborted set was itself composed of songs from two other scrapped projects. The first was Dream Factory, an album Prince made with unprecedented input from the Revolution -- especially keyboardist Lisa Coleman and guitarist Wendy Melvoin. The other was Camille, in which Prince sang with sped-up vocals to play the androgynous title character. Camille was mostly a solo affair, though Wendy and Lisa made notable contributions to at least one song, “Strange Relationship.”

When his label shot down Crystal Ball, Prince nixed seven songs, altered the tracklist, and wound up with Sign O’ the Times, an album unlike anything in his or anyone’s else’s catalog. Working closely with engineer Susan Rogers, he fired up his beloved LinnDrum and mined the newfangled Fairlight CMI digital sampler for stock sounds. All of this gave the songs a dry, mechanized funkiness that complemented his fiercely unique songwriting.

After opening Sign O’ the Times with the topical title track, Prince digs into some favorite topics: God, music, sex, and romance. His explorations of that last subject on songs like “If I Was Your Girlfriend” and “Strange Relationship” (largely scrubbed of Wendy and Lisa’s contributions) reveal a songwriter whose imaginative, insightful lyricism rivaled his wily musicality.

Fans will argue about how much influence Wendy, Lisa, or the other members of the Revolution had on Sign O’ the Times, since he played nearly everything himself, but there’s no denying the album’s brilliance. Its 16 songs can really only be compared to each other, so to celebrate the 30th anniversary, we’ve ranked the tracks from best to worst -- or in this case, from greatest to slightly less great.

1. “Adore”: Prince saves the best for last with this smoldering old-school ballad, reportedly inspired by Wendy’s sister Susannah, his fiancée at the time. Much of Sign O’ the Times succeeds because Prince is doing things no one else can. On “Adore,” he works within the parameters of classic R&B -- drums, organ, horns, vocals layered like tiers on a wedding cake --and simply beats every other loverman at his game. This song is tender, sexy, and -- thanks to the multi-tracked vocals around 3:00 -- damn funny. Just as one Prince gets done granting his girl permission to smash up his car, another interjects, “Well, maybe not the ride…”

2. “I Could Never Take the Place of Your Man”: This paisley power-pop earworm represents something truly unusual in rock ‘n’ roll: a song where a guy tries to talk a woman out of having sex with him. The lyrics tell of a wronged single mother searching for a little affection. Prince admits he “may be qualified for a one-night stand,” but he knows what really brought this woman to the bar on Friday night, and it’s nothing he’s prepared to offer.

3. “Sign O’ the Times”: With little more than a stiff robo-funk beat and some bluesy guitar licks, Prince does “What’s Going On” for 1987. As he tackles AIDS, gangs, drugs, natural disasters, and even the Challenger explosion, Prince plays it cool and detached. “Sign O’ the Times” is a status update, not a call to action. His solution isn’t marching in the streets or phoning your congressman. “Hurry, before it’s too late,” he sings, echoing the carpe diem message of “1999” and “Let’s Go Crazy.” “Let’s fall in love, get married, have a baby.”

4. “If I Was Your Girlfriend”: Books could be written about this pleading synth-pop oddity. Using his Camille voice, Prince tries to win back an ex-lover by asking her to imagine him as her female friend -- someone she wouldn’t think twice about crying with at the movies or confiding in about heartbreak. Or undressing in front of. In the final minute, as Camille’s rap gets increasingly sexual, seriously creepy keyboards swell up under the mix. “If I Was Your Girlfriend” is either a sincere attempt to relate to the opposite sex or a super-devious ploy to get laid. Maybe it can be both.

5. “The Ballad of Dorothy Parker”: According to engineer Susan Rogers, a studio power outage led to the melting-cassette sound of this warped pop parable about a sassy waitress and the healing powers of bubble baths. Prince never seals the deal Dorothy, but he comes away from their encounter with more than soggy jeans and a Joni Mitchell song stuck in his head. Dorothy sends him back to his troubled relationship with the tools he needs to stop the fighting and actually be a “real man,” even if he insists on ordering fruit cocktail.

6. “Strange Relationship”: This slinking, stomping Camille jam features one of Prince’s all-time best opening lines: “I guess you know me well, I don't like winter / But I seem to get a kick out of doing you cold.” It gets downright frigid from there, as Camille outlines a twisted love affair that’s destined to end badly. Backing vocals from soon-to-be-ousted Wendy and Lisa add an extra layer of complexity to this dark and seductive cut.

7. “Starfish and Coffee”: Sweet as jam from those opening piano chords, “Starfish and Coffee” was inspired by an eccentric classmate the Melvoin sisters had growing up. The innocence and playfulness -- plus the magical-realist surprise ending that’s really no surprise at all -- make this track a welcome addition to an otherwise adult-themed album.

8. “Slow Love”: Slow jams don’t get any classier than this. With moonlight pouring through the drapes and horn men Eric Leeds and Atlanta Bliss blowing sweet nothings out on the lawn, Prince exhibits some uncommon carnal patience. It’s a song about two lovers, but lots of people helped Prince bring it to life. Co-writing credit on the jazzy white-glove R&B affair goes to Prince’s onetime paramour Carole Davis. Wendy and Lisa grab background vocals, and composer Clare Fischer adds the orchestration.

9. “Housequake”: A puckish Camille presides over this mutant James Brown throwdown, telling everyone how and when to dance and calling “bullshit!” on those who front like they know what the funk is going on. It’s a dictatorship on this dancefloor ‘til the cops shut it down.

10. “Forever In My Life”: Another studio mishap led to Prince’s backing vocal coming in ahead of the lead one. That works perfectly in the context of this song, all about a guy wanting to finally settle down and get married. The calmer Prince who jumps out in front clears a path for the more passionate guy embarking on this monogamous adventure. In the last 30 seconds, Prince adds some acoustic guitar, perhaps to offset the coldness of the groove.

11. “U Got the Look”: The biggest single off Sign O’ the Times (No. 2 on the Billboard Hot 100) may be the album’s most straightforward lusty rock song. But it’s far from ordinary. Prince goes into Camille mode and duets with a sultry Sheena Easton, who swings for the fences in this “World Series of love.” The flat beat and distorted guitars were inspired by Robert Palmer’s “Addicted to Love,” and Sheila E’s drumming gives the whole thing a rattling, ramshackle feel.

12. “It’s Gonna Be a Beautiful Night”: An extended dance break between “The Cross” and “Adore,” track 15 is a ferocious nine-minute live jam recorded in Paris on Prince’s Parade tour. Despite the ominous Wizard of Oz “oh-we-oh” chant, “Beautiful Night” is a utopian fantasy akin to the next song on this list. Sheila E. raps an Edward Lear poem and Prince goes into James Brown mode, calling out commands to the band over sizzling chicken-grease guitar. The coolest part comes at the very end: Prince calls, “Confusion!” and it’s like the piano goes tumbling down the stairs.

13. “Play In the Sunshine”: This euphoric psych-funk love-fest features some bonkers lyrics (“We’re gonna love all our enemies / ‘til the gorilla falls off the wall”) and breathtaking guitar, bass, synth, and drug programming from Prince. The utopian vibe counterbalances the bleakness of the preceding track ("Sign O' the Times"), like Prince is showing us just how funky the future can be.

14. “The Cross”: If all Christian rock were this raw and emotional, holy rollers might gain a few more converts. As “The Cross” builds from a gently strummed ballad to a scraping slice of Eastern-flavored garage rock, Prince wails raspily about how Jesus is returning to solve the world’s problems. His conviction mitigates the preachiness, and his self-harmonizing vocals in the closing seconds capture the warmth of his message.

15. “Hot Thing”: The hottest thing on this skeevy psych-funk banger is Eric Leeds’ saxophone. In a few different places, his frenzied blowing pushes the whole thing wonderfully over the top. By the end, he’s left sputtering, spent from the preceding five minutes of freakiness.

16. “It”: This thumping confession of sexual obsession isn’t all that interesting until the final 90 seconds, when Prince starts whispering and the synths and orchestra take it to sci-fi territory.