They may attract Sufi-dancing Deadheads to their rock-club shows and they may have connections to lower Manhattan's art-music scene, but when you get right down to it, Medeski Martin & Wood are just a jazz organ trio. Organist John Medeski, drummer Billy Martin, and bassist Chris Wood don't work a whole lot differently from the old Jimmy Smith Trio; they get a good groove going, add a catchy hook and then improvise changes on both the rhythm and the melody. They may take more liberties than Smith ever has, but that familiar combination of a thick organ sound and funky drum patterns is still the core. The third Medeski Martin & Wood album, Friday Afternoon in the Universe, is the best reflection yet of the trio's live show, for 13 of the 15 tracks feature no guests, just the interaction among the three principals. And that interaction has been honed by three years of extensive roadwork into a genuine give-and-take. There's no parade of disconnected solos here, no fast, flashy playing for its own sake; the three players move as one through impressionistic, atmospheric patches into driving funk grooves and then off onto spacey tangents. Medeski plays some piano and synthesizer, but everything he plays has the thickened textures associated with a B-3 organ--thick enough to make three pieces more than sufficient. --Geoffrey Himes