The guitar-driven "Dreamer," released as part of 2009's triple-album Lotusflow3r set, built upon an underrated part of Prince's legacy: His role as a fighter for justice.

The track, which questioned just how far we'd come in the wake of Martin Luther King Jr.'s grisly murder, evolved out of a series of informal, round-table discussions organized by Tavis Smiley. With Prince's encouragement, the television host began inviting select guests back home for continuing post-show talks. As they delved into topics of both recent and historical import, Prince drank it all in.

"He wanted me to bring certain panelists over to the house with me for a sort of academic after party," Smiley told USA Today in 2016. "I'd always oblige, and everybody from Cornel West to Dick Gregory would sit around his table dissecting the political, economic, social and cultural issues confronting the black community in particular, the nation and the world. I've never met a more curious mind."

"Dreamer" would ultimately be dedicated to Gregory – a comedian turned civil-rights activist who died in August – as Prince extended his own ever-lengthening parallel musical conversation about our country's political and moral choices.

He perhaps most memorably called out President Reagan's Cold War policies with "Ronnie Talk to Russia" from 1981's Controversy, but by then Prince had already offered a searing anti-war message on 1980's "Partyup." He also took on society's inattention to the sick and poor with 1987's "Sign O' the Times," and then with "Dance On" in 1988. "We March," from 1995's The Gold Experience, made a clarion call for collective action against racism. West also overdubbed spoken word passages onto a new version of "Dear Mr. Man," which was first released on 2004's Musicology.

Gregory, meanwhile, emerged from a tumultuous era having pioneered many of these same arguments. The first African-American stand-up to work a white comedy club, and the first to take a seat next to Jack Parr on the original Tonight Show, Gregory was a staunch opponent of the Vietnam War, a friend to both King and Malcolm X, and a determined activist. He marched at Selma, Ala., was shot while on a peacekeeping mission during the 1965 riots in Watts, and performed a series of benefit shows encouraging equality. He also dabbled in conspiracy theories that intrigued Prince, as well.

Their paths almost seemed destined to cross. "Dick Gregory really moved me and a lot of my friends," Prince told Tavis Smiley in 2009. "I show [his recordings] to everybody who comes over the house. Especially white folks, because they need to hear that, so that they know more about all of us – because what he said affects all of us."

"Dreamer," which perhaps dates back to sessions for 2006's 3121, showcased a tight trio featuring C.C. and Josh Dunham on drums and bass. Together, they gird Prince's searing commentary on the racial divide with one of his grungiest (and most surprising) grooves.

Prince had only recently returned to the guitar after serving as a sideman on a series of 2006 dates with singer Tamar Davis. With the spotlight pointed elsewhere, he began to focus solely on riffs and solos, and his long-held passion for the instrument was reborn. "Dreamer" was subsequently nominated for a Grammy in the best solo rock vocal performance category, but lost in 2009 to Bruce Springsteen.

Unfortunately, many of the issues Prince dealt with continued to plaque society – and his lyrics here ("Have you ever clutched the steerin' wheel in your car too tight / Prayin' that the police sirens just pass you by that night") proved eerily prophetic. By 2012, Prince could be found anonymously donating funds to support Trayvon Martin's family after the teen was killed. The in-custody death of teenager Freddie Gray prompted "Baltimore" from 2015's Hit n Run Phase Two. That track also referenced Michael Brown, another black youngster who had been killed the year before by police in Ferguson, Mo.

Prince was moved to play host to a Rally 4 Peace benefit concert in Baltimore, and later helped inspire YesWeCode – a program meant to involve more African-American youngsters in technology as a pathway out of poverty and crime.

"Every time you see a black kid wearing a hoodie, you say: 'There's a thug,'" Prince told activist and commentator Van Jones, via USA Today. "If you see a white kid wearing hoodie, you say: 'There's Mark Zuckerberg.'" When Jones countered that racism was to blame, Prince replied: "Maybe so, or maybe you civil rights guys haven't created enough Mark Zuckerbergs."

Prince promoted YesWeCode's efforts via a headlining performance at the 2015 Essence Festival, the same year he made a stark comparison on stage at the Grammy awards: "Like books and black lives," Prince said, "albums still matter – tonight, and always."

Moments like "Dreamer," so full of sharp recriminations and fiery outrage, are one of the reasons why.

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