There are a couple of things: I'm still hoping to coax a few people, who tell me they are lurking, to join in. I find the textbook (which I chose) to be difficult when I don't read it just the right way. I don't want other people to fall into some of the same holes I have. What I SHOULD have said earlier is that I've had difficulty with the book for reasons that are INCIDENTAL to Scheme programming. (In my case, it's that I've put some miserable experiences in high school math classes out of my mind, along with the math itself.) So Jon rightly responded by listing things that are good about Scheme. I don't understand them, but presumably I will eventually if I persist. So far, from Jon's list of Scheme features, I only recall one that has been clearly addressed so far in SICP, namely the concept of first class functions. P.S. Jon, I haven't studied you examples yet, neither these latest nor the ones you pointed to before. I'll get to them eventually.