There are plenty of pianists who impress us with their technical prowess, and there are two dozen or so who enlighten us with their wisdom. But there are only a handful who impress and enlighten us, and Maurizio Pollini belongs in this category. Noted for his crystalline interpretations of modern masterpieces,the Italian pianist can also transform the simplest Mozart sonata into an elevating experience and the most intellectual Beethoven sonata into an emotional catharsis. At this recital, Pollini will play an early Beethoven (Piano Sonata no. 4 in E-flat) and one of the composer's most sublime and experimental sonatas (no. 30 in E Major). I'm also looking forward to the Chopin Etudes. Written by the great Polish composer for his pupils--mostly young Parisian ladies--they are miniatures of seeming improvisation in which sentimental expression and rapid fingerwork are delivered in equal doses. The twelfth in the set, nicknamed the "Revolutionary," is a wonder of sound and fury--supposedly reflecting Chopin's anguish at the capture of Warsaw by the Russians. Sunday, 3 PM, Orchestra Hall, 220 S. Michigan; 435-6666.