As one of the first albums Herbie Hancock recorded after departing Miles Davis' quintet in 1968, as well as his final album for Blue Note, The Prisoner is one of Hancock's most ambitious efforts. Assembling a nonet that features Joe Henderson (tenor sax, alto flute), Johnny Coles (flugelhorn), Garnett Brown (trombone), Buster Williams (bass), and Albert "Tootie" Heath (drums), he has created his grandest work since My Point of View. Unlike that effort, The Prisoner has a specific concept -- it's a tribute to Dr. Martin Luther King, evoking his spirit and dreams through spacious, exploratory post-bop. Often, the music doesn't follow conventional patterns, but that doesn't mean that it's alienating or inaccessible. It is certainly challenging, but Hancock's compositions (and his arrangement of Charles Williams' "Firewater") have enough melody and space to allow listeners into the album. Throughout the record, Hancock, Coles, and Henderson exchange provocative, unpredictable solos that build upon the stark melodies and sober mood of the music. The tone is not of sorrow or celebration, but of reflection and contemplation, and on that level, The Prisoner succeeds handsomely, even if the music meanders a little too often to be judged a complete success.