The book of Daniel is divided into two sections. Chs. 1-6 are in story form with some poetry. Chs. 7-12 are essentially apocalyptic literature, mostly in prose form and concerned with the relationship of a series of kingdoms to God's people. This literature is futuristic, extending to the end times.
The book is written in two languages, with 1:1-2:4a and chs. 8-12 in Hebrew, whereas 2:4b through 7:28 are in Aramaic.
Each story opens with the chief character troubled by a difficult problem and forced to make a decision related to a life-threatening crisis. In a miraculous way, God provided aid, which resolved the crisis and brought glory to his name.
Each story is written in the third person, except for 4:1-27, 34-37, which are in the first person. Within these stories are five poems in the NIV text: 2:20-23; 4:3, 34-35; 5:25-28; 6:26b-27.
In chs. 7-12, the visions experienced by Daniel and interpreted by angels are in narrative prose. In the NIV text, 7:9-10 is in poetic form. Both the visions and the interpretations are marked by symbolic images, metaphors, similes, and other figures of speech.
The cardinal doctrine in the book is the sovereignty of God over all nations and their potentates. Daniel and his friends were hostages. Repeatedly their lives were in danger because of their total commitment to their God and his laws. God powerfully delivered them, and mighty rulers acclaimed the supremacy of the one true God.
Three vicious beasts and a horrible monster, representing four empires, threatened the existence of the people of God, but a Messiah was promised who would save them. Finally God would resurrect the righteous to everlasting life and the unrighteous to face contempt. To the holy ones the book has a theology of hope; to the wicked it has a theology of divine justice that punishes wicked rulers and brings empires to ruin.
The book amply illustrates the reliability of divine revelation about the future. Not only were the symbols of dreams and visions in accord with present reality, they were in accord with future events that God brought to pass. God has a plan of judgment for the wicked and a plan of redemption for those who trust in him, and he faithfully carries those plans out.
The book also highlights the effectiveness of prayer as a means: (1) to discover the will of God; (2) to obtain courage to make a total commitment regardless of circumstances; (3) to obtain assurance that God will be with those in danger even unto death; (4) to confess one's own sins and the sins of one's people; and (5) to petition God for fulfillment of the prophecy of a previous prophet, in this case Jeremiah (9:2-3). The book testifies that these prayers were heard and answered by a gracious God in his own remarkable way.