Michael Tilson Thomas' long association with the music of George Gershwin results in performances so idiomatic they could be categorized as (almost) definitive. In all three works, Thomas not only reveals Gershwin's compositional genius but also wonderfully captures the composer's trademark playful swagger. This quality comes through strongest in Rhapsody in Blue, here in its original jazz band orchestration with Thomas impressively performing double-duty as pianist and conductor. Even Bernstein's storied (and cut, and mannered) CBS performance can't match the heightened bawdiness of Thomas' reading. The New World Symphony sounds remarkably like the virtuoso big bands of the jazz age. 　　In An American in Paris, Thomas' lucid conducting exposes the manifold brilliance of Gershwin's multi-layered orchestration. But most impressive is the Piano Concerto in F, where Garrick Ohlsson's bluesy demeanor and virtuoso fingerwork, along with Thomas' smooth tempos and deft phrasing, confirm the greatness of Gershwin's work--fully the equal of contemporary concertos by Prokofiev or Ravel. The San Francisco Symphony provides powerful and joyfully-executed readings of both pieces, while RCA's high-impact, natural sound makes for an enticing listening experience. In sum, a must-have Gershwin disc.