The new rules Keith Jarrett has made for himself in solo performance are firmly in play on the two-disc Carnegie Hall Concert, recorded in the Isaac Stern Auditorium in September of 2005. Those who found his earlier solo recordings -- from Vienna and Köln to La Scala -- to be compelling might be a bit disconcerted at first, because of the completely different approach Jarrett has taken to improvising. His concert is divided into shorter segments, or parts, and often changes direction numerous times in the course of a single piece. Indeed, the impression is given almost of composed songs where harmony, melody, and rhythm are pulled to the breaking point and reassembled along new lines. And even in more angular or turbulent sections, Jarrett's ideas are drenched in lyric ideas. Whether he is playing against himself contrapuntally, entering into a difficult chromatic interlude, or opening onto a pastoral sonic field, his notion of "song" prevails. His more knotty and immediate approach is full of wonderful ideas, sometimes deeply serious, at others humorous and beguiling. But there isn't a dull moment. Indeed, if the audience -- which contained many critics and musicians -- is any indication, the electricity carried over the stage both ways. There are ten parts that make up the concert proper, and on disc two, five short encore pieces that run from four to six minutes in length, culminating in his only standard, with a beautiful reading of "Time on My Hands." His beautiful reading of "My Song" (from a quartet recording in 1977) is here, restated with consummate grace. This is a Jarrett solo set for the ages; it showcases, since his full return in 1997, his renewed and restless commitment to the music and to himself as an artist.