Our concert program consisted of Brahms and Beethoven piano and cello sonatas, a cello suite by Bach, and a piano sonata by Mozart. Though of the highest artistic level, in chamber music he was a different Horowitz from what his clamoring audience expected. / After the delicate Mozart piano sonata there were demands for an encore. “What shall I do? What shall I do? It’s a chamber music concert,” he said between taking bows. / “Hell, give them what they want,” I said, clapping his shoulder. / He certainly did. Chopin mazurkas and polonaises, some Liszt and Dohnanyi made Brahms, Beethoven, Bach, and Mozart forgotten preliminaries.