Daniel was a prophet of the late Babylonian exile period. The book is of the apocalyptic genre in the same class as Ezekiel, Zechariah and Revelation. The period is during that of the successive world powers of Babylonia, the Medes and the Persians and Persia. The inspired author of the book is not known. However, it may well have been the prophet, Daniel, himself.
Half of the book, chapters 1-6, is about the Israelite and government official, Daniel, and his friends. It shows them faithfully serving the one true God-Yahweh, the God (Elohim) of Israel. They were faithful to God at the risk of their lives.
The second half of the book, chapters 7-12, gives us the dreams/visions of the Prophet Daniel. These dreams/visions range from easy to understand to very difficult, if not impossible, to understand. One thing is clear. God Almighty is in ultimate control of human history from the time of Daniel to the end times and the final establishment of the Kingdom of God.