I just got back from San Francisco, where I gave a keynote lecture about how our bodies are like ponds, and why doctors need to think like ecologists. It takes a lot of time for me to put these talks together, and so I like to share them afterwards with more people than those who were physically in the room with me. Sometimes the people who invite me videotape the lectures and put them online. (Example: A talk I gave about science and the media.)

Other times, I make an audio recording and merge it with the slides to create a video. (Example: A talk about Neanderthals.) Still other times, I turn my lecture notes into an essay,