Delivered in the fall of 1973 and collectively titled "The Unanswered Question," Leonard Bernstein's lectures covered a lot of terrain, touching on poetry, linguistics, philosophy and physics. But the focus inevitably comes back to music -- to how music works, or to the underlying grammar of music. The lectures run over 11 hours.
​The lectures are considered masterpieces, beautiful examples of how to make complicated material accessible. 
The sound starts when Mr. Bernstein begins to speak