In many ways Leonard Bernstein and George Gershwin were very similar: both were great showmen, at ease with different kinds of music, and both were superb performers. On this essential recording, Bernstein the pianist gives a winningly loose-limbed performance of Gershwin’s Rhapsody in Blue and conducts a near-ideal An American in Paris. Bernstein’s own Symphonic Dances from West Side Story sizzle, and his searing film score about life on the New Jersey docks, On the Waterfront, just oozes atmosphere and angst.