There are numerous synonyms for the word "book", which can be used to add variety and interest to your writing or conversation. Some common synonyms include tome, volume, publication, manuscript, text, work, treatise, and opus. Additionally, you can use more specific synonyms depending on the type of book, such as novel, guide, manual, encyclopedia, dictionary, biography, autobiography, or anthology. If you want to emphasize the physical aspect of a book, you can use words such as hardcover, paperback, journal, diary, or notebook. And, if you want to convey a sense of importance or literary significance, you can use synonyms like classic, masterpiece, epic, or canonical work.