Marc Ribot is best known as the guitarist who helped to define Tom Waits' "Rain Dogs"-era sound with his spiky, skronky approach, and as the thinking rock star's session guitarist of choice, utilized by Elvis Costello, Marianne Faithfull, David Sylvian and many others. But although he has branched out of it with great success, Ribot is best seen as the leading light of New York's downtown jazz and free improv scene, which he helped to define as a key member of John Lurie's Lounge Lizards and as one of John Zorn's favorite collaborators. His new Spiritual Unity band, his best in years, is Ribot's tribute to one of his heroes, the great free jazz saxophonist Albert Ayler. In putting together the band -- and seeking Ayler's spirit, not his sound -- Ribot astutely left out saxophone and instead called on trumpeter Roy Campbell and drummer Chad Taylor, and pulled out a trump card in the person of 70-year-old Henry Grimes, a recently rediscovered bassist who has a wonderfully deep and woody sound and once played on some of Ayler's classic sessions. Together, they made one of the best jazz recordings of 2005, chasing transcendence through dogged, sloppy simplicity and sheer force of will, and nailing Ayler's elusive barbaric yawp of ecstasy.