Songs in the Key of Life is the eighteenth studio album by American singer, songwriter and musician Stevie Wonder. It was released on September 28, 1976, by Tamla Records, a division of Motown. The double album has been regarded by music journalists as the culmination of Wonder's "classic period" of recording. The album was recorded primarily at Crystal Sound studio in Hollywood, with some sessions recorded at the Record Plant in Hollywood, the Record Plant in Sausalito, and The Hit Factory in New York City; final mixing was conducted at Crystal Sound.By 1974, Wonder was one of the most successful figures in popular music; Wonder's previous albums Music of My Mind, Talking Book, Innervisions and Fulfillingness' First Finale were all back-to-back critical successes. However, by the end of 1975, Wonder seriously considered quitting the music industry and planned to emigrate to Ghana to work with disabled children. Plans for a farewell concert had begun, but Wonder subsequently changed his mind and signed a new contract with Motown on August 5, 1975. This outlined a seven-year, seven-album, $37 million deal with full artistic control. At the time, it was the biggest recording deal in history.Songs in the Key of Life was released as a double LP with a four-song bonus EP. It debuted at number one on the Billboard Pop Albums Chart becoming only the third album to achieve that feat and the first by an American artist at the time. Both the lead single "I Wish" and follow-up single "Sir Duke" reached number one on the Billboard Hot 100. Songs in the Key of Life spent thirteen consecutive weeks at number one on the Billboard 200, becoming the album with the most weeks at number one during the year. It was the second best-selling album of 1977 in the US. In 2005, Songs in the Key of Life was certified Diamond by the Recording Industry Association of America (RIAA). Songs in the Key of Life won Album of the Year at the 19th Grammy Awards. It is the best-selling and most critically acclaimed album of Wonder's career. Widely regarded as Wonder's magnum opus and one of the greatest albums in the history of recorded music, many musicians have remarked on the quality of the album and its influence on their own work; indeed, some notable musicians have named it as the greatest album of all time. It was voted number 89 in Colin Larkin's All Time Top 1000 Albums and ranked number 4 on Rolling Stone's list of The 500 Greatest Albums of All Time. In 2002, it was inducted into the Grammy Hall of Fame. In 2005, Songs in the Key of Life was inducted into the National Recording Registry by the Library of Congress, which deemed it "culturally, historically, or aesthetically significant.