Pianist Orion Weiss constructs Ravel’s “musical tomb” of Couperin, commemorating the French baroque but — more importantly — paying tribute to several of Ravel’s friends who died in battle during World War I. While the movement titles are historic, the harmonies are pure Ravel: sparkling figurations alternate with emotionally-charged melodies. Shostakovich’s rarely performed second piano sonata, another wartime piece, was written in 1943 during the Siege of Leningrad; its bitingly sarcastic opening gives way to melodies of limpid beauty and an enigmatic finale. Brahms’ Op. 122, preludes for organ based on German chorales, is his final work, completed shortly before his death. He lived just long enough to see these gems transcribed for piano by his close friend, Ferrucio Busoni.