In movies and television, Hitler’s speaking voice is usually depicted as a dialed-back version of his public speaking performances: even in private he’s either shrieking or muttering. The reality, captured only once in a secret recording made in Finland, is unnerving. It’s deep and commanding, yet with the same maniacal rhythms. You almost forget that he’s admitting, in 1942, that he underestimated Soviet productive capability and would have ignored anyone who told him.