10. Mose Allison There wasn't a whole lot of singing on Mose Allison's 1957 debut, Back Country Suite, but it gives a good idea of his burgeoning relaxed vocal delivery, as well as his strong piano skills. While Allison clearly has a deep affinity for bop on the disc, he also shows his love for the blues, especially on "One Room Country Shack." Since then, Allison has released some great recordings where he delves into both jazz and blues realms.

9. Jimmy Scott One of the most intriguing voices in jazz, Jimmy Scott -- sometimes know as Little Jimmy Scott -- has a peculiarly high voice due to Kallmann syndrome, a condition that stunted his growth and prevented him from experiencing puberty. His '60s Savoy releases, in particular, are great, especially The Fabulous Songs of Jimmy Scott. While his singing career took a back seat to various jobs for the next few decades, his career had something of a re-birth after singing at the funeral of his friend, the legendary Doc Pomus in 1991, and Scott went on to release some outstanding albums since then, like Holding Back the Years and The Source.

8. Mark Murphy While he was born when some of the singers on this list were just starting out their careers, Mark Murphy got his start as a pop singer during the '50s and soon delved into jazz, taking a few cues from Jon Hendricks, and Murphy developed his own brand of vocalese. He released a number of albums under his own name, including his 1956 Verve debut, Meet Mark Murphy, and one of his finest recordings, 1978's Stolen Moments. Along the way, he picked up six Grammy nominations for Best Jazz Vocal Performance.