I recently learned that the world is a less wonderful place with the death of my friend and former teacher, David Santos. Only a few months ago I wrote a blog post in which my praise for his teaching featured prominently. I knew he read it at the time, because he sent me brief comment about it. I was just told by a friend of his that he (David) was very happy by what I had written, and so the eulogy will quote extensively from it. It makes me glad that I happened to write that blog post earlier this year, not realizing what the none-too-distant future held. And it serves as a reminder not to assume that you’ll always have a chance later to tell people things you’d like them to know. I’m going to do my best to take this lesson to heart. So if you get a message (or Facebook comment or whatever) from me with some out-of-the-blue remark, it may be because you’re important enough to me that I want to say it (whatever it is) while we’re both fortunate enough to be here.