What I have always lamented about Bill Withers is that he often isn’t included in the mainstream pantheon of the Great Black Soul Singers. Perhaps that’s because of his unconventional path to musical success.

He began adulthood in the military, joining in 1956 at age 17, before moving to Los Angeles in 1967. While trying to get his music career off the ground, he worked in various factories, doing assembly work, saving money to record his own demo tapes. He refused to quit his job at Weber Aircraft, even after he got signed to Sussex Records in 1970.

Withers kept working, installing toilet seats for commercial airplanes. His debut album “Just As I Am,” was released that next year, and on its cover, there is Withers, 32, leaning on a wall outside Weber Aircraft, lunchbox in hand.

In this story, there is no romantic mythology of a childhood prodigy, or someone who blew the roof off a church in a small town before being driven off in a Cadillac to go make hit records. If there is a mythology of Withers it is one of the working everyday man. He was the first man in his family to not work in the coal mines of West Virginia. And he had enough of a life before music to know how to walk away from it when he’d had enough.

In 1985, he became fed up with white record executives trying to tell him how and what to sing, or how to promote his album. He didn’t release any new music for the last 35 years of his life.

Withers, in both formal interviews and informally recorded banter, could sometimes be crass, even abrasive, but rarely was he oversentimental. For this, the sentimental moments within his music feel more vulnerable and float above the emptiness of the feel-good machinery within so much of the celebrity-media industrial complex — the mutually assured sanitized reproduction of life.

Near the end of the 1973 BBC concert, Withers shifts from his guitar over to a piano to play a singular rendition of “Lean On Me,” his ode to the selfless and shared duty of friendship, written after he moved to Los Angeles and longed for everyone he loved back in West Virginia.