During one of my frequent searches for composers whose music I've never head, I stumbled upon Nikolai Karlovich Medtner (1880-1951), a Russian born composer and pianist considered my many to be a young contemporary of Rachmaninov. Medtner mostly composed works for the piano, and of those works, his piano sonatas are most notable. The piece I happened to find was his Sonata Tragica, Op. 39, No. 5. Watch a video of Sonata Tragica
(the sound cuts out at the 4:30 mark, but returns a minute and a half later). The work was composed as the fifth part of Medtner's Second Cycle of Forgotten Melodies and was intended to be played in pair with Canzona matinata (number four in the cycle).