Okay, the user wants me to translate "cook-book" into Vietnamese. Let me check the rules again. The first rule says to translate all content into Vietnamese. The second rule mentions if it's already in Vietnamese, leave it as is. The third rule is to provide only the translation without explanations.
So, "cook-book" in English is a book with recipes. In Vietnamese, the direct translation would be "sách nấu ăn". I need to make sure that's the correct term. Sometimes, "cookbook" can be translated as "sách nấu ăn" or "sổ tay nấu ăn", but "sách nấu ăn" is the most common. The user didn't specify any particular context, so the straightforward translation should be fine. No need for explanations, just the translation. Let me confirm once more. Yes, "cook-book" becomes "sách nấu ăn" in Vietnamese. I'll output that.