The Schematics of Computation

I like this text very much. I originally used it as a text for an upper level undergraduate course on programming languages. I still occasioanlly refer back to it as I feel that it introduces several concepts in a very accessible way suitable for those looking for a foundation to do advanced work in computer science. I do feel, however, that the book is sadly getting a bit dated. I would update the historical notes to be more relevant to current readers and also I would make the book's reference implementation of scheme to be one of the major scheme distributions such as chez or plt .