10. Chaka Khan
Who: Chaka Khan is a powerful-voiced singer who got her big break in the 1970s as a member of the funk-R&B band Rufus.
When: Active from 1972-Present.
What: Her hits with Rufus included "Tell Me Something Good" and "Sweet Thing." Her solo hits include the songs "I'm Every Woman," "I Feel For You" and "Through the Fire."
Why: Very few singers have been able to remain relevant as long as she has, and fewer still have voices anywhere near as strong as hers is, even after four decades of singing.
Who: Donny Hathway is a legendary Soul singer whose career spanned the 1970s before ending suddenly when he was 33.
When: Active from 1970-1979.
What: His biggest hits were duets with Roberta Flack: "Where is the Love" and "The Closer I Get to You," both of which reached No. 1 on the R&B charts.
Why: Despite dying tragically in the 1970s, Donny many of today's R&B and Soul artists have cited him as an influence, including John Legend, India.Arie, Brian McKnight and of course, Donny's daughter, Lalah Hathaway.
Who: Patti Labelle is one of the most powerful, razor sharp singers in music history. As a member of the trio Labelle and later as a solo artist, she helped set the standard for vocal firepower.
When: Active from 1961-Present.
What: Her hits included "Lady Marmalade" in 1974 with the group Labelle, the solo hits "If You Only Knew," "Love, Need and Want You" and "New Attitude."
Why: Few singers within R&B or outside of it are on her level. And even after 50 years in the music game, she still has far greater skills than most vocalists a fraction of her age.
7. Marvin Gaye
Who: Marvin Gaye was one of Motown's biggest singers in the '70s, but he was also an accomplished drummer and played percussion on numerous hits by other singers signed to the label at the time.
When: Active from he early 1960s-1984.
What: He had many, many hits as a solo artist and with labelmate Tammi Terrell. They include "What's Going On," "Let's Get It On," "Ain't Nothing Like the Real Thing" and "You're All I Need to Get By."
Why: Marvin not only had one of the smoothest voices of his era, but unlike most artists of his day, he also tackled social issues in songs like "Mercy Mercy Me (the Ecology)," "Inner City Blues (Make Me Wanna Holler") and "Flyin' High (in the Friendly Sky)."
Who: Stevie Wonder is one of America's greatest singer-songwriters and had a long string of hit songs from the 1960s through the '80s.
When: Active from 1962-Present.
What: His first hit single was "Fingertips (Pt. 2)" in 1963, when he was just 13 years old. Since then, his chart-topping songs have included "I Was Made to Love Her" in 1967; "Signed, Sealed, Delivered, I'm Yours" in 1970; and "I Just Called to Say I Love You" in 1983.
Why: Despite being blind, Stevie managed to become one of the most creative singer-musicians of the Motown era. He's also won more than two dozen Grammys during his career.
Who: Mary J. Blige is a New York-born R&B/Soul singer whose early songs were so rap-influenced that they earned her the nickname "the Queen of Hip-Hop Soul."
When: Active from 1992-Present.
What: Songs of hers that have reached No. 1 on the R&B charts include "You Remind Me" in 1992; "Not Gon' Cry" in 1996; "Family Affair" in 2001; and "Be Without You" in 2005.
Why: Almost no woman in R&B and Soul carries as much passion and energy in her voice as Mary. She's also one of the most versatile vocalists ever; to date, she's the only performer in music history to have won Grammys in the R&B, Pop, Gospel and Rap categories.
4. R. Kelly
Who: R. Kelly, the self-proclaimed "Pied Piper of R&B" is one of the most creative writers, singers and producers in the music business today. He also has a history, however, of questionable activity in his personal life.
When: Active from 1992-Present.
What: His biggest hits include the Grammy-winning inspirational anthem "I Believe I Can Fly," the sexually-charged "Bump n' Grind" and the drama-soaked "Down Low (Nobody Has to Know)."
Why: He's ranked this high partially because of his amazing versatility and partially because few artists can match his record of producing successful songs for himself and others.
3. Otis Redding
Who: Otis Redding, aka The King of Soul, was a Southern-bred singer whose rich, full singing voice virtually dripped with raw power and emotion.
When: Active from 1962-1967.
What: His hits included "Mr. Pitiful," "I've Been Loving You Too Long (to Stop Now)" and the Grammy-winning "(Sittin' On) The Dock of the Bay."
Why: While many of the male artists on this list are known for buttery-smooth vocals, Otis dared to be different from the norm by nurturing a deeper, more gritty style of singing.
2. James Brown
Who: James Brown, aka The Godfather of Soul, aka Mr. Dynamite, aka, Mr. Please Please Please, was an R&B, Funk and Soul music pioneer, as well as a outstanding all-around entertainer.
When: Active from 1959-2006.
What: His No. 1 R&B hits include "Try Me," in 1958; 1964's "Papa's Got a Brand New Bag;" 1968's "(Say It Loud) I'm Black & I'm Proud;" and 1974's "The Payback."
Why: James was not only a highly-charged vocalist, but an amazing all-around entertainer. He was a founding father of the Funk and Soul movements and was a direct influence on the stage shows of many artists that came after him, including Michael Jackson and Prince.
Who: Aretha Franklin, aka the Queen of Soul, is the most vocally powerful singer in R&B/Soul music history. She has a string of hits that dates back decades.
When: Active from 1956-Present.
What: Among her most famous songs are "Respect," "Chain of Fools," "Something He Can Feel," "Jump to It" and "Freeway of Love," all of which topped Billboard's R&B songs chart between the mid-1960s and mid-1980s.
Why: Sheer vocal singing ability. No one on this list can match her ability and versatility. As her nickname implies, Aretha is music royalty; few artists are as revered as her, or have matched her commercial success and critical acclaim.