1. The Grateful Dead's "other" guitarist and lead vocalist: Bob Weir
2. Jamaica's most famous singer and musician: Bob Marley
3. Early blues guitarist who supposedly sold his soul to the devil in exchange for his ability to play: Robert Johnson
4. Led Zeppelin's lead singer: Robert Plant
5. He leads the "Family Band": Robert Randolph
6. He imitated Boris Karloff on his "Monster Mash": Bobby "Boris" Pickett
7. "My Prerogative" singer better known now as Whitney Houston's ex-husband: Bobby Brown
8. Legendary folk-rocker whose songs include "Positively 4th Street" and "Like a Rolling Stone": Bob Dylan
9. Chicago's Mr. Chops, often considered the band's social conscience in the early days: Robert Lamm
10. With his Gang, he recorded such hits as "Jungle Boogie" and "Ladies' Night": Robert "Kool" Bell
11. Singer of "Mack the Knife" and "Beyond the Sea": Bobby Darin
12. Kris Kristofferson song made famous by Janis Joplin: "Me and Bobby McGee"
13. Matchbox Twenty singer who also collaborated with Carlos Santana: Rob Thomas
14. He was "Addicted to Love" in 1986: Robert Palmer
15. Canadian First Nations member of The Band who also wrote "Broken Arrow": Robbie Robertson
16. They fought the law, and the law won: Bobby Fuller Four
17. He fronted the Silver Bullet Band: Bob Seger

Bonus: Former Take That singer who has had numerous Number Ones in Great Britain, but is virtually unknown in the United States: Robbie Williams