Not entirely the point of the book, but I found that the first chapter of Gödel, Escher, Bach: An Eternal Golden Braid (which discusses formal systems, symbol m

Not entirely the point of the book, but I found that the first chapter of Gödel, Escher, Bach: An Eternal Golden Braid (which discusses formal systems, symbol manipulation and how that relates to thinking) was a catalyst for me to tighten up my thinking processes.