The phrase "the Good Book" is typically used to refer to the Christian Bible, but there are a variety of synonyms that can be used in its place. Some common alternatives include "the Holy Scripture," "the Word of God," or simply "the Bible." Other phrases that may be used in religious contexts include "the Book of Life," "the Sacred Text," or "the Divine Gospel." Additionally, for those seeking a more informal or colloquial term, "the Good Word" or simply "God's Word" may suffice. Ultimately, the choice of synonym will depend on the speaker or writer's personal preferences and intended audience.