We all know there are rock "concept" albums - otherwise, Roger Dean would be out of work.  But is there such a thing as a jazz concept album?  Mike's skeptical, but Pat argues all you need is a unified mood and, maybe in the case of Herbie Mann, a tab of acid or two.  The Session – COLLUSION; Herbie Mann – STONE FLUTE; Gerald Wilson – ETERNAL EQUINOX; Wynton Marsalis – CITI MOVEMENT; Henry Threadgill – RAG, BUSH AND ALL.