By Kim Ruehl Folk Music Expert By Kim Ruehl These days, when people think of "folk music," they usually picture a singer-songwriter with an acoustic guitar. But, believe it or not, the singer-songwriter is a fairly recent phenomenon in the centuries-old history of American folk music. Though there were singer-songwriters who preceded Woody Guthrie, he was really the first person to popularize the format, passing on the torch to Bob Dylan (who took the whole singer-songwriter thing to a new level) and so on. In popular music, the songwriters were always totally separate from the singers, so the popularization of American folk music via the singer-songwriter in the middle of the 20th Century helped to turn the pop market on its head, as well.? If you're a fan of singer-songwriters and want to learn more about the roots of that format in American folk music, read on for some of the essential, most influential folk singer-songwriters.? Al Aumuller/New York World-Telegram and the Sun/Library of Congress/Public Domain 1. Woody Guthrie Woody Guthrie wrote literally thousands of songs during his lifetime, and many of them have gone down not only in history, but also in the cover-tune repertoires of bands from Folk and Bluegrass to Rock and Roll. His songs reported labor conditions and the feelings of generations of Americans, and have inspired historians, labor unions, and countless musicians. Heck, he even made it onto a postage stamp! More » continue reading below our video Celebrity Breakups of 2015 We Didn't See Coming Essential Pete Seeger. © Sony Legacy 2. Pete Seeger Pete Seeger's career began shortly after Woody Guthrie's, though his upbringing in New England was quite a bit different from that of his friend and contemporary. He started out as a journalism major at Harvard, before ditching school and setting out with a banjo to write folk songs. First as a member of the Almanac Singers (with Guthrie, Lee Hays, and others), then as a founding member of the Weavers, and later as a solo artist, Seeger has perfected the art of writing the simplest, most catchy songs for social justice.? More » Bob Dylan's debut album. © Sony/Columbia 3. Bob Dylan In the 1960s when folk music started resurging out of the San Francisco and Greenwich Village Folk scenes, Bob Dylan quickly became one of the forerunners of the movement. He adapted Woody Guthrie's talkin' blues style and brought topical Folk songs to a new generation. His original songs have inspired generations of musicians all over the country, and in all genres; and his voice is quite possibly one of the most distinguishable in Folk music. More » Joni Mitchell. © Steve Dulson 4. Joni Mitchell Joni was one of the first real legendary woman singer/songwriters. Her simple, pretty melodies tackled everything from relationships to the War in Vietnam. Her work has inspired men and women all over the musical spectrum, and her songs continue to be covered by singer/songwriters and rock bands alike. More » Phil Ochs. © Robert Corwin 5. Phil Ochs Phil is one of the lesser known troubadors of the 1960s folk scene, but he's certainly one of the most important. His topical songs tackled everything and everyone, and nothing was too taboo to write about. His songs like "Love me, I'm a Liberal" and "I'm Not Marching Anymore" enjoyed huge popularity. Phil was a major player in the War is Over movement of the Vietnam era, and his songs from that period are covered even today. More » Paul Simon live at Glastonbury. photo: Dave J. Hogan/Getty Images 6. Paul Simon Originally one half of Simon & Garfunkel, Paul went on to become one of the most influential and groundbreaking Singer/Songwriters in the 1980s. His Graceland CD won a slew of Grammy Awards in 1987. Paul's American and world Folk music influences have produced some of the most beautiful and innovative Folk tunes that have inspired the a wave of Singer/Songwriters. More » Cat Stevens - 'Gold'. © Island records 7. Cat Stevens Certainly one of the most prolific Singer/Songwriters, Cat Stevens is also one of the most memorable. His songs have been covered by bands all over the country and the musical spectrum. Tunes like "Wild Word" and "Peace Train" are simply unforgattable, timeless classics. More » Janis Ian. promo photo 8. Janis Ian Another incredibly prolific Singer/Songwriter is Janis Ian. Her career started when she was just a teenager, but she's continued to pump out record after record of fantastic Folk music. Her songs are timely, topical, and poignant, and cover everything from relationships to her longing for world peace. More » Greg Brown. promo photo 9. Greg Brown Since the late 70s, Greg Brown has been one of the most fantastic Singer/Songwriters of his generation. His songs have been featured on movie soundtracks and in compilations, and he continues to be a favorite at the festivals each year. His low, grumbly voice can be hypnotic as he sings through songs about everything from war to peace, and even life on the farm in Iowa. More » Ani DiFranco. © Danny Clinch 10. Ani Difranco Ani is one of those people who has changed the way people think of Folk music. Her innovative guitar technique (she turns her strumming hand into a "claw" through the cunning use of fake nails and electrical tape), and her unbeatably loyal fan base make her a force to be reckoned with. She started her career in her late teens, and since then has produced dozens of records and averaged hundreds of shows per year on tour. More »