Beethoven’s “Waldstein” Sonata, No. 21 of his 32, is one of the pinnacles of his so-called Middle Period—10 astoundingly productive years that also gave us the Fifth Symphony, Violin Concerto, and Fidelio. Powerful, hugely ambitious, and form-expanding, the “Waldstein” (immortalizing his friend and patron Count Waldstein) has drama in spades, and throws down many challenges for the pianist. And on this classic recording, the Russian Emil Gilels perfectly conveys its nobility and technical brilliance, beautifully gauging the sonata’s magnificent architecture. Its two companions here—both also high points of the Middle Period, and both superbly played—merely confirm this recording’s peerless status.