UNIQUE IN IT'S CONTINUITY.
Here is a book:
1.   Written over a 1,500 year span.
2.   Written over 40 generations.
3.   Written by over 40 authors from every walk of life including kings, peasants, philosophers, fishermen, poets, statesmen, scholars, etc.:
Moses, a political leader, trained in the universities of Egypt
Peter, a fisherman
Amos, a herdsman
Joshua, a military general
Nehemiah, a cupbearer
Daniel, a prime minister
Luke, a doctor
Solomon, a king
Matthew, a tax collector
Paul, a rabbi
4.        Written in different places:
Moses in the wilderness
Jeremiah in a dungeon
Daniel on a hillside and in a palace
Paul inside prison walls
Luke while traveling
John on the isle of Patmos
Others in the rigors of a military campaign
5.        Written at different times: David in times of war Solomon in times of peace
6.   Written during different moods:
Some writing from the heights of joy and others writing from the depths of sorrow and despair
7.        Written on three continents:
Asia,
Africa
and Europe
8.        Written in three languages:
Hebrew: Was the language of the Old Testament In II Kings 18:26-28 called "the language of Judah." In Isaiah 19:18 called "the language of Canaan."
Aramaic: Was the "common language" of the Near East until the time of Alexander the Great (6th century B.C. - 4th century B.C.) 32/218
Greek: New Testament language. Was the international language at the time of Christ,
9.        Its subject matter includes hundreds of controversial subjects. A controversial subject is one which would create opposing opinions when mentioned or discussed.

        Quoted from Evidence that demand a verdict - Josh McDowell