Yes, "by the book" is a very commonly used metaphor in English, even when no book is involved. It's roughly equal to saying that you are doing something strict

Yes, "by the book" is a very commonly used metaphor in English, even when no book is involved. It's roughly equal to saying that you are doing something strictly by the rules (and the rules don't have to be contained in a book or even exist in text form). Some uses would be like: "My boss insists on doing everything by the book".