Celebrate the 47th anniversary of the release of Stevie Wonder's "Songs in the Key of Life" by watching this documentary

Stevie Wonder's epic album "Songs in the Key of Life" was released on September 28, 1976. This 1996 installment of the Classic Albums series is a great document of the album's making, with interviews with Stevie and contributing musicians and engineers.

At the time, Wonder had just signed the biggest music contract in history to that point: a $13 million seven-year deal he signed with Motown in 1975. By 1976, CEO Barry Gordy was getting frantic because he'd paid so much money, and that first album was so late (Wonder had started recording in 1974). But Wonder came through, inaugurating the biggest music contract of all time with the best [citation: me] album of all time.

Gordy says in the documentary: "I must admit I was extremely unhappy about the 13 million dollars. Of course, until 'Songs in the Key of Life' was released, and it came in at number one. Then, I thought, 'What a brilliant negotiator you are,'"' to myself."

Wonder's recording of "Songs in the Key of Life" has become legendary, as all involved say he worked around the clock for years in a burst of creativity, and expected his musicians to keep up with him. Bassist Nathan Watts says his bass playing on "I Wish" sounds angry because he was angry when he recorded it.

"That was cut at 3am at Crystal on a Jazz Bass I had bought. I had been recording all day, and I had just gotten home and into bed exhausted, when Stevie called and said, "I need you to come back – I've got this bad song." I came in and he had the 8th note keyboard bassline, so I joined in, adding my Jamerson grace-notes, which he liked. Then he said, 'Nate, do this,' and he sang some growly roars – so I started adding my slides. The engineer, Gary Olazabal, suggested I plug into an Ampeg tube preamp, which he drove to get the growl. Other than that, the slides sound angry because it was 3 in the morning!

At 11:11, Wonder reveals that what I always thought was a charming little fill in the genius harmonica solo on "Isn't She Lovely" was a mistake. When they isolate the harmonica at the sound board, Wonder says, "I'll admit to that mistake."

At 18:04, Wonder recreates the writing of "I Wish," as well as his drumming. "After we did the keyboards, I then put a drum track down." Wonder often played many of the instruments himself, much to the consternation of the musicians who were often camped out in the studio for hours and days waiting to be called upon.

At 36:38, there's a revealing moment with Wonder and guitarist Michael Sembello, who co-wrote the lyrics for "Saturn." Wonder had originally written "Going Back to Saginaw," the Michigan city Wonder is from. When Sembello momentarily misheard it as "Going Back to Saturn," it took on a new meaning, with Saturn representing a "shangri-la, or a perfect kind of place where people are realizing their true potential as spiritual beings."

At 58:56, Wonder and engineers John Fischbach and Gary Olazabal isolate various elements of the multi-layered "Black Man," and it's fascinating. Wonder says he remembers working on this song in the studio on the Bicentennial, July 4, 1976, which he says inspired him. Olazabal jokes, "So you didn't give us the Fourth of July off."

(Whenever I see an old music documentary with the engineers and artists at a sound board isolating tracks of a classic album, I worry that those masters were destroyed in the Universal fire.)

There's no album I've listened to as many times as "Songs in the Key of Life," and it's not close. It's been a big part of my life ever since I was a kid and I first heard "Sir Duke" on the radio, and sat bolt upright, thinking, "What is that, and how do I get it?"

Thank you, Stevie! Now release the hundreds (!) of songs you recorded in those sessions that didn't make the album!

As one of the musicians understates about the album when they're all gathered together at a reunion, "I thought it was one of the best works he's done. That has come out! Because we all know what's in the can!"