God's special people, the Jews, did not obey God. So God punished them. He allowed the king of Babylon and his army to defeat them. The king of Babylon forced most Jews to live in Babylon. Babylon was a long way from their own country.
A young man called Daniel was among the people who went to live in Babylon.
The first part of the book of Daniel in the Bible tells some stories from the life of Daniel and his friends. Many times the people of Babylon tried to make them forget the real God and to serve false gods. The people of Babylon even tried to kill Daniel and his friends because they would not serve the false gods. But Daniel and his friends were loyal to the real God. Daniel became a very important man in the government of Babylon.
The second part of the book of Daniel tells about Daniel's dreams. These were strange dreams. Sometimes Daniel was awake when he had his dreams. These were special dreams that God sent to Daniel to tell him what would happen in the future. Some things that Daniel saw in his dreams have now happened. Other things that God told Daniel in his dreams have not happened yet. But God is in control of the future. God will do what he has promised.