"The Structure and Interpretation of the Computer Science Curriculum" https://users.cs.northwestern.edu/~robby/pubs/papers/htdp-si...

The authors of HtDP on SICP.

HTDP is (quite a bit) easier, and only really derived from the first few chapters of SICP if that. The course I recommend as a pre-req is actually based of HTDP, I think it really helps with the much more comprehensive SICP