The self-imposed quarantine on solo concerts over, Keith Jarrett returned to the improvisatory format that he virtually invented, mellower and more devotional than ever. Indeed, within the 38 minutes of solo improvisation captured at Paris's Salle Pleyel, Jarrett pulls further away from the old rousing (and thoroughly American) gospel, blues and folk roots of earlier concerts toward a more abstract concept. Opening with a soaring, lyrical canonic melody, he rambles through his familiar obsessive hammering, grand tremolos, and the like before topping it off with an ethereal tune that turns somber. There are two encores --Russ Freeman's"The Wind," awhich begins with a brief swatch of Steve Reich-like minimalism but swiftly turns reflective the rest of the way, and "Blues," a welcome if brief return to one of the pianist's root sources. Again, Jarrett's virtuosic abilities are never in doubt, and he rarely flaunts his technique for its own sake, but one senses that the inspiration level is down; one doesn't come out of the CD all charged up as with many earlier solo concerts.