"but if I decide to learn (say) compilation for real then I'd be better served by reading a book focused on compilation."
If you're a total noob at compilers, as I was when I read SICP (and still am) I think chapters 4 and 5 are a great intro. Like other Lisp/Scheme compiler and PL books (Lisp in Small Pieces, PLAI I think, EOPL to a lesser extent, parts of PAIP I think) SICP doesn't scratch parsing and lexing, but just uses (read). This means you can get to interesting stuff like program analysis and code generation without getting bogged down in parsing, at least at first. It's a really nice approach to learning that stuff.
If you're a total noob at compilers, as I was when I read SICP (and still am) I think chapters 4 and 5 are a great intro. Like other Lisp/Scheme compiler and PL books (Lisp in Small Pieces, PLAI I think, EOPL to a lesser extent, parts of PAIP I think) SICP doesn't scratch parsing and lexing, but just uses (read). This means you can get to interesting stuff like program analysis and code generation without getting bogged down in parsing, at least at first. It's a really nice approach to learning that stuff.