After running off a rapid-fire string of hits and a shelf full of Grammy awards in the early Seventies, Stevie Wonder signed an unprecedented $13 million contract renewal with Motown Records — and then he made them wait. And wait and wait. Two-plus years passed after 1974’s Fulfillingness’ First Finale, an eternity in R&B. But when he delivered Songs in the Key of Life, a double-album with a bonus EP included, there was no doubt that the wait was worth it. It topped the charts for almost three months, and featured more true classics than even most great artists write in a lifetime. Celebrating childhood (“I Wish”), jazz (“Sir Duke”), and the beginnings of life itself (“Isn’t She Lovely”), Songs in the Key of Life was a powerhouse — a rare moment when a master was faced with a new level of pressure, and responded by taking his game to new heights.