The four Gospels, Matthew, Mark, Luke, and John, are examples of books which did not carry the names of their actual authors. The present names were assigned long after these four books were written. In spite of what the Gospel authors say, biblical scholars are now almost unanimously agreed that none of the Gospel authors was either a disciple of Jesus or an eyewitness to his ministry. Although some books of the Bible are traditionally attributed to a single author, many are actually the work of multiple authors. Genesis and John are two examples of multiple authorship.
Many biblical books have the earmarks of fiction.
For example, private conversations are often related when no reporter was present. Conversations between God and various individuals are recorded. Prehistoric events are given in great detail. When a story is told by more than one author, there are usually significant differences. The Flood story is an example of this kind of adaptation.