One of the non-obvious things about SICP is that there is a lot of really good stuff in the footnotes and the exercises. You aren't doing yourself any favors if you skim over either of them.
Indeed, a download and quick look shows that the book has a lot more content than just a sequence of lessons. I've immersed in the foreword, and enjoying it greatly. The best textbooks are not just informative, but written to be enjoyed as literature.