When John Coltrane expanded his traditional quartet by adding a young, little-known saxophonist from Little Rock, Ark., it wasn't so he could take a break. Coltrane knew Pharoah Sanders was a soul mate ready to accompany him on an exploration of the jazz universe's outer limits. Indeed, Sanders often sounded like he had never set foot on the planet.

On the final recordings of Coltrane's radical restructuring of jazz, such as "Ascension" and "Meditations," Sanders' contribution was essential. Although they journeyed together only three years, the Sanders-Coltrane pairing still stands as one of the most provocative in modal jazz. Their music left the traditional structures of jazz in a state of conceptual disarray, threatened by these entirely new conceptions of rhythm, harmony and improvisation.

After Coltrane's death, Sanders, in collaboration with others in the inner circle, carried on with open-ended, free-form soloing, often filling entire LPs with one continuous musical statement. In the '80s, though, Sanders cooled somewhat, returning to a traditional jazz quartet to develop the lyricism that was often ignored in his explosive early work. The '90s found him teaming up with producer Bill Laswell for a mix of jazz with African, world music and layers of electronics and synthesizers.