This is really from times before OB, and might be all too obvious, but the most important thing I’ve learned from your writings (so far) is bayesian probability. I had come in touch with the concept previously, but I didn’t understand it fully or understand why it was very important until I read your early explanatory essays on the topic. When you write your book, I’m sure that you will not neglect to include really good explanations of these things, suitable for people who have never heard of them before, but since no one else has mentioned it in this thread so far, I thought I might.