Garrick Ohlsson, a student of Claudio Arrau, entered the Juilliard School at 13, and in 1970, at 22, he became the first American to win the prestigious International Chopin Competition in Warsaw. He's probably best known for his Chopin--he's recorded the complete works--but last year in Switzerland he performed all 32 Beethoven sonatas, a monumental feat he's repeating this summer at Ravinia and Tanglewood. The five CDs of Beethoven sonatas he's recorded show an incredible technique and a sound that can be enormous yet sensitive in quieter moments. His tempi can be a little slow, which sometimes allows for more clarity and greater attention to dynamics and articulation, as in the first movement of the Pathetique. But sometimes, as in the allegro molto of the Sonata op. 110, slowness becomes lethargy. Still, most of the playing is very good, and the Ravinia performances are likely to be solid. Monday's program consists of sonatas no. 1, 17 (the Tempest), 12, and 18; Tuesday's of no. 7, 13, and 29 (the enormous Hammerklavier). Mon 6/19, 8 PM, Martin Theatre, Ravinia Festival, Green Bay & Lake Cook Rds., Highland Park, 847-266-5100, $10-$40.