An album-length suite (four themes, related by a four-note motif, separated by different improvisational approaches) by John Coltrane, the culmination of his quartet's exploration and extension of modal jazz. Trane's liner notes made explicit the spiritual underpinnings of his post-Miles music, and gave a hint of the libretto for the
next phase in his career. Also the original title of Spike Lee's film Mo Better Blues.