With his creativity growing by leaps and bounds, Wonder soon felt limited by Motown's strict production and publishing contracts. When his record contract expired in 1971, Wonder recorded two full albums by himself and used them as a bargaining tool during contract negotiations with Motown. The record label gave him total artistic control of his albums, as well as the rights to his own songs. Soon afterwards, the two albums -- Where I'm Coming From and Music of My Mind -- were released.

Music of My Mind, especially, helped usher in a new era of soul/R&B. Along with Sly Stone and Marvin Gaye, Wonder was responsible for making soul and R&B albums not just collections of singles, but cohesive artistic statements, where artists could extend their music beyond the confines of a three-minute hit single. With his next two albums, Talking Book and Innervisions, Wonder's music became richly complex and inventive; in addition to his musical innovations, Wonder's lyrics addressed social and racial issues as eloquently and incisively as any other pop songwriter. Wonder sustained his creative peak through 1974's Fulfillingness' First Finale and 1976's Songs in the Key of Life.

Three years later, he released the ambitious and bewildering Journey Through the Secret Life of Plants, which received terrible reviews upon its release. Wonder released the more straightforward Hotter than July in 1980; the album received substantially better reviews and became his first platinum album. However, he wasn't able to sustain that momentum for the rest of the decade. Although his records sold well and he scored the occasional hit -- including the smash hit ballad "I Just Called to Say I Love You" -- his albums weren't as focused as they were a decade earlier. By the '90s, he was still an immensely respected musician, but his music was no longer on the cutting edge.