The Holy Bible is a book containing chapters that describe events connected to helping people to understand God's Will. The Old Testament contains chapters about events before the coming of Jesus, and the New Testament contains chapters about the events of the life of Jesus and after.
Events of the Old Testament are largely shared by Jews (the Hebrew Bible) and by Christians. The word of the Old Testament part of the Bible is also accepted by Muslims. This is the reason that all three religions are called 'religions of the Book'. However, the interpretations are different in some respects.