Joan Baez has yet to be nominated despite being emblematic of Sixties folk and protest music, both as a Newport Folk Festival fixture and Woodstock performer, a model for folkies and social-minded musicians to come. And though her tumultuous relationship with Bob Dylan is well remembered, she was also responsible for many in non-folk circles first getting to hear him, as one of the first artists to cover his songs. "I worshiped her.… She just changed my whole focus on music," Emmylou Harris told Rolling Stone. "I just admire her also as a person, how she's put herself out there in the fight for human rights all around the world."

Not only is Dolly Parton a force of nature in Nashville, but a hugely prolific songwriter with more than 100 million album sales, a movie star ("the quintessential … whatever it is," 9 to 5 costar Lily Tomlin told Rolling Stone), a multi-Grammy winner and Oscar nominee, a sometime traditionalist (as part of the millions-selling Trio with Emmylou Harris and Linda Ronstadt) and hero to countless artists country and otherwise. That includes Whitney Houston, whose biggest hit was once Parton's. "I think Dolly Parton is a hell of a writer and a hell of a singer," Houston said in 1993. "I was so concerned when I sang ["I Will Always Love You"], how she'd feel about it, in terms of the arrangement, my licks, my flavor. When she said she was floored, that meant so much to me."

The Jackson 5 was inducted into the Rock & Roll Hall of Fame in 1997 and Michael Jackson was inducted as a solo artist in 2001 — is their younger sister not far behind? From the release of her 1987 breakthrough Control all the way through last year's assured Unbreakable, Janet Jackson has been at the forefront of R&B-infused pop, trying everything from Joni Mitchell samples to New Jack Swing-nodding bravado, then transforming them into incredibly catchy declarations of intent: Ten Hot 100 Number One Singles is no joke. "As a production, I thought the Rhythm Nation album is like one of the most incredible albums in history," said Stevie Wonder, "the subject matter and the feeling of it all. And [Janet] sounded really incredible as well."

Carole King is, rightly, already part of the Hall of Fame as a Brill Building writer —she's even said that she sees herself as "first, last and always a songwriter." But the performing half of her career, kickstarted by frequent collaborator James Taylor, is certainly of merit. 1971's Tapestry, which sold 25 million copies in America, is the model for uncountable singer-songwriters since, folk and otherwise. King's beloved as much for her writing as for her lived-in performance, curiously difficult to replicate despite dozens of artists adopting her songs as their own. "Carole knew exactly what she wanted," drummer Russell Kunkel told Rolling Stone. "If she didn't like what you were doing, she would tell you what to play."

"Walkin' After Midnight," "I Fall To Pieces," "Crazy" — these songs helped define not just country music, but American popular music in the post-war era. Patsy Cline's tremulous contralto helped make those songs indelible. It also helped her reach equal footing with her male compatriots. Cline died in 1963, before she had a chance to complete her fourth album — which was slated to be her full-on crossover from country. But artists ranging from Loretta Lynn to Marc Ribot have shown that even her most down-home records influenced the wider world of music. "I remember my dad telling me to listen to the way she told a story," said LeAnn Rimes. "I remember feeling more emotion when she sang than anyone else I had ever heard." 

Willie Mae Thornton was one of rock & roll's earliest innovators; she laid down a gloriously sexy version of "Hound Dog" before Elvis had ever heard it and wrote "Ball and Chain," which became one of Rock Hall inductee Janis Joplin's signature songs. The Alabama-born belter's raunchy performance style caused songwriter Jerry Lieber to dub her "the saltiest chick Mike [Stoller] and I have ever seen," and it inspired countless performers.

These days, Loretta Lynn is largely praised for her unflinching social commentary on tracks like "The Pill," "Coal Miner's Daughter" and "Dear Uncle Sam." But even more so, her frankness and generosity toward her audience, in particular toward working-class women, can be seen echoed in the work of the best women in country today, as well as bands such as the White Stripes. "Loretta has some sort of instinctive ability to write naturally, realistically, and 'pop constructively' at the same time," said Jack White. "She has a sort of backward, double-chorus signature style that you don't see often. I'm often curious if this is an accident and she just focused on it, or if it comes from inside her naturally." 

Whitney Houston's voice is without compare, the K2 every R&B diva longs to scale. She's endlessly versatile, growing from ebullient ("How Will I Know") to imperious ("I Have Nothing") and embodying every gradation of skill and emotion in between. For this alone — and the accompanying tons of album sales — her absence from the Hall of Fame is noted. But arguably more important is the late musician's unparalleled role in opening doors for black women: Houston, after years of fighting for respect, was one of the first to receive heavy rotation in MTV's early years, and she is the model for essentially every R&B-pop crossover artist since. "Whitney's voice was so pure and powerful. She had so much control and range and expressive ability," John Legend told Rolling Stone after Houston's death. "We really lost one of the greatest singers we'll ever hear. She was that good. "

Nina, the embattled Nina Simone biopic, is due to arrive next week to what can charitably be called tepid anticipation. If anything, though, it's a testament to just how far-reaching the musician and activist's impact is: being cited by a huge swath of artists like Lauryn Hill, Erykah Badu and perennially, John Lennon. The middle eight of the Beatles' "Michelle" is a take on Simone's version of "I Put a Spell on You," and when Simone released her "Revolution" in the same year as the Fab Four's single, Lennon told Rolling Stone he admired "somebody who reacted immediately to what I had said." She fought for civil rights with a level of passion and impact that few popular musicians have matched since. "Most people are afraid to be as honest as she lived," Qubilah Shabazz said in the excellent Simone documentary, What Happened, Miss Simone? "She was not at odds with the times. Times was at odds with her."

"I make records my way," artist-musician-philosopher Yoko Ono told Rolling Stone earlier this year while promoting Yes, I'm A Witch Too — a remix album she released at the age of 83. Ono's unique take on music, which mirrored her avant-garde art and frequently showcased her guttural shrieks, helped bring outré concepts closer to the musical mainstream. Even albums that were derided at the time have proven themselves to be touchstones for generations of experimental musicians. Her collaborations with her former husband John Lennon — including their 1980 album Double Fantasy, which won the Album of the Year Grammy in 1981 — contained some of her most accessible work, but she's also worked with and inspired a slew of musicians operating on the fringes, from Sonic Youth's Kim Gordon and Thurston Moore to storied saxophonist Ornette Coleman.  

Girl groups, a cornerstone of the Sixties, are underrepresented in the Hall of Fame, save the Supremes, the Shirelles, the Ronettes and Martha and the Vandellas. In the Crystals' case, the waters are muddied by producer Phil Spector's spotty history with (among many other things) credits. Darlene Love, inducted in 2011, is celebrated in some part for singing on some of the Crystals' biggest hits, including the entirety of "He's a Rebel" (to the Crystals' wry surprise, upon first hearing it on radio). But even so, the Crystals are responsible for some of the genre's most-beloved songs — like the pure, swooning expression of joy "Then He Kissed Me." As one of Spector's earliest groups, they rocketed the producer to fame and have been cited by Bryan Ferry, Bob Dylan, Martin Scorsese and countless others.

If the Crystals represent the joy of girl groups, the Shangri-Las exemplify the heartbreak, the rueful morning to the blissful night. The two sibling sets from Queens imbued tracks like "Leader of the Pack," "I Can Never Go Home Anymore" and "Past, Present and Future" with a toughness barely concealing vulnerability, backed by classical-indebted arrangements that cast their frank scenarios in a vaguely unreal haze. As such, they're perhaps the girl group most beloved of critics and rock fans, and undoubtedly the one that modern girl groups and retro-styled singers (not to mention punk and grunge bands, among other seemingly unlikely followers) are most indebted to. "Amy Winehouse played ['Remember (Walking in the Sand'] for me the first day that we met," Mark Ronson told Rolling Stone last year. "I listened to it that night and came up with the main piano chords for 'Back to Black.'"

Kicking off her career with the wounded, yet stalwart "Don't Make Me Over," the voice of Dionne Warwick defined the sound of R&B. Her delicate phrasing and gospel-inspired power resulted in some of the catchiest songs of the Sixties, including a series of collaborations with Burt Bacharach and Hal David, and she became the first African-American woman to perform for the Queen of England in 1968, the same year that the Bacharach-David composition "Do You Know The Way to San Jose" scaled the charts. Warwick had her ups and downs during the Seventies, but her 1985 smash "That's What Friends Are For," which she cut with high-powered pals (and Hall of Fame members) Elton John, Gladys Knight, and Stevie Wonder, was one of pop activism's higher points in an era filled with cause-minded tracks. 

The trio of Patti Labelle, Nona Hendryx and Sarah Dash initially worked in doo-wop, and were the "Sweethearts of the Apollo" because of their frequent appearances at the famed Harlem theater. In the Seventies, after moving to London, they reinvented themselves as Labelle, gaining critical acclaim for their fusion of gospel and rock, then moved fully into the pop world with an outrageously catchy fusion of funk, glam and soul, accentuated by eye-popping outfits. "When we started as Labelle, we set ourselves goals, aims and dreams," Patti Labelle told The Chicago Defender in 1975. "We wanted to dress to our individual identities, not to mention our fantasies, and give the audience something to really groove on visually as well as musically." Labelle broke up in 1976, launching the storied solo careers of its individual members, and their influence can be felt in contemporary R&B groups like Destiny's Child and En Vogue. "Lady Marmalade" has enough enduring appeal that it hit Number One again when Christina Aguilera, Lil' Kim, Mýa and Pink covered it in 2001. "She makes lyrics come alive," said producer Kenny Gamble of Patti Labelle. "And after all these years of singing, she's hitting notes that some opera stars can't." 

As a songwriter, Bush is among her genre's most omnivorous: the Bush glossary includes stylized super-sexualized violin fantasies, affairs with snowmen, Houdini and Hitler, a proto-Red Wedding, 150 digits of pi, nuclear fallout, Vietnam and gay rights. As a relatively young artist, she pioneered the hyper-theatrical, choreographed modern rock tour — and then promptly quit tours, legacy secured, until 2015. There's also the small matter of Bush's directly or indirectly influencing a huge swath of songwriters and artists since, including, famously, Outkast's Big Boi. "What caught me the most [about Bush's music] was, first, the production and the voice of course, but also the different meanings behind the stories she was telling," the rapper told Rolling Stone in 2011.