[mulcahey]

+ 1 for GEB. I read that freshman year (now a junior).

As an example of its utility, I really like its description of formal systems which are a somewhat simplified version of context free grammars. There are many other concepts described in that book that give similar but more intuitive explanations of CS concepts that helped me understand them as part of "the bigger picture."

CODE: The Hidden Language of Computer Hardware and Software, which is mentioned on here a lot, was helpful for similar reasons.