The more I read, the more I think Leon Russell is Advanced. Check out a bit of this article from townonline.com:
Leon Russell, estimable keyboardist and "The Master of Space Time." He has spent time onstage or in the recording studio with all of the above, as part of the legendary "Wrecking Crew" consortium of Los Angeles studio musicians. He has had a remarkable solo career, and, as he prepares for a show at the Firehouse in Newburyport next week, is closing in on his 50th year as a performer.
If you have listened to radio in the last 50 years, you've heard the multi-instrumentalist. The leonine, shaggy Russell has played keyboards, guitar, horns and a variety of other instruments on some of the most influential songs and albums in rock, rhythm, soul, blues and pop music. Beyond his supporting role on hundreds of records, Russell has had a solo career that saw him become one of the most popular touring and recording artists of the '70s. With his full-length white hair and beard, Russell remains a striking figure.
He started performing in clubs at the tender age of 14, in his home state of Oklahoma. A quirky Oklahoma law that made that possible. "I'm just thankful that I grew up in a 'dry' state so I was able to, with the absence of liquor laws, begin playing night clubs at the age of 14," he says. Not long after, Russell ended up as part of a Jerry Lee Lewis' road band, touring the states for two years. By 18, Russell decided to become a full-time musician rather than go to college, and settled in Los Angeles. There, his elegant chops swept him into the legendary group of L.A. session musicians collectively known as "The Wrecking Crew." These men and women were the rhythmic and melodic underpinning of literally hundreds of records during the late '50s and early '60s.
Phil Spector's inimitable "Wall of Sound" was built around Wrecking Crew stalwarts like bassist Carol Kaye, jazz guitarist Barney Kessell, guitarists Glen Campbell and Tommy Tedesco, legendary drummer Hal Blaine, sax player Steve Douglas, Mac Rebennack ("Dr John") and Sonny Bono, and backup vocals were provided by myriad artists including Sonny Bono's girlfriend Cherylin Sarkassian (later to be famous as Cher).
n addition to working with the eccentric genius (and current murder suspect) Phil Spector, Leon played on many Beach Boy songs, including "California Girls." He can be heard on The Byrds' first hit, "Turn, Turn, Turn." He played on Jan and Dean's "Surf City;" A job being a job, he can be heard on Massachusetts native Bobby Boris Pickett's "Monster Mash LP."
Russell appears to have been a veritable sponge of the different musical styles and voices swirling around him. At home with thumping gospel, ballads, jazz and blues, rockabilly, country and straight rock 'n' roll, he has emerged as a senior statesman in the music business, a survivor and an amalgam of sounds stretching across the musical spectrum.
Although his voice, which ranges from achingly expressive to quirky and breathless, is his most strikingly apparent musical asset, it is his instrumental prowess that has garnered the most professional admiration. Jack Nietzsche, producer for Spector who went on to work with Neil Young and Randy Newman, is quoted as saying that "Leon was there for the solos and the fancy stuff."
That, and a streak of brilliant songs that have been covered by artists ranging from Joe Cocker to George Benson, The Carpenters to Willie Nelson.
The article goes on for a few more pages. I think a little more aural research might be in order.