The Bible has 66 books in the Protestant tradition. They were written by many authors, in different countries and over several hundred years. Exact dates are disputed, and we do not know the names of all the authors.
The Old Testament
It was written mainly in Hebrew, with some parts in Aramaic. It contains laws, history, poetry, wisdom sayings and prophets. Many of the texts were told orally and gathered and edited over time.
The New Testament
It was written in Greek during the first century. It has four Gospels about Jesus, an account of the first church, letters from Paul and others, and Revelation.
People and God
Many Christians believe that God spoke through the people who wrote, but that they wrote in their own time, in their own style and in their own words. How much weight is placed on one or the other varies between churches.
How were the books gathered?
The church gathered the books gradually, and the list of books (the canon) was largely settled in the first centuries. Catholic and Orthodox churches have a few more books in the Old Testament than Protestants.