Just dropped in to post something while I had a moment. Not long ago, I mentioned Feynman's Messenger Lectures to someone in conversation. Feynman, in addition to being a bang-up physicist, was also an intensely charismatic man, and an engaging public speaker. People got him in front of a camera more often later in his life, after he'd written his books of memoirs and observations, but he did a lot of speaking earlier in his career as well. He had a tendency to want to explain complicated science to people who had no idea what he was talking about -- although they often did by the time he was done, which is no mean feat when you teach quantum electrodynamics in your professional life. The BBC kindly turned up to tape a series of physics lectures for laypersons at Cornell, called the Messenger Lectures, with their expensive and characteristically misaligned quad tape apparatuses. These are educational, and so far as I know, free for use under that guideline; they are, of cours...