The books take several forms: pre-history, law, history, prophecy, apocalyptic writings, wisdom, poetry or song, legends, “lives” (tales of heroic persons), gospels and letters. Each form has certain conventions and exists to serve certain purposes. Taken together, the books convey a certain people’s experiences of God. The books use many images and tell many stories, some of which contradict one another. Those contradictions and different accounts aren’t unexpected in what was originally oral tradition.
The Bible we receive was put together by religious leaders. Certain books were excluded from the “canon” of Scripture, because they were deemed to lack a certain authority or, as in the case of the Gnostic books, because they contained ways of understanding God that the dominant group found offensive and threatening.