(All recorded lectures are complete. Lectures I, XI, and XII were not recorded. The sound quality of this series is mixed. The recording of lecture VI has audience noise and a hiss sound on the tape, and the sound of lecture VII is very poor, with audience noise and a buzz sound at the beginning, echo noise throughout, and occasional ringing sound. The voice is best for recordings of lectures IV, V, IX, XIII and XIV. The question periods for all the lectures are hard to hear.)