The Book of Tobit, named after its principal hero, combines specifically Jewish piety and morality with oriental folklore in a fascinating story that has enjoyed wide popularity in both Jewish and Christian circles. Prayers, psalms, and words of wisdom, as well as the skillfully constructed story itself, provide valuable insights into the faith and the religious milieu of its unknown author. The book was probably written early in the second century B.C.; it is not known where.

Tobit, a devout and wealthy Israelite living among the captives deported to Nineveh from the northern kingdom of Israel in 721 B.C., suffers severe reverses and is finally blinded. Because of his misfortunes he begs the Lord to let him die. But recalling the large sum he had formerly deposited in far-off Media, he sends his son Tobiah there to bring back the money. In Media, at this same time, a young woman, Sarah, also prays for death, because she has lost seven husbands, each killed in turn on his wedding night by the demon Asmodeus. God hears the prayers of Tobit and Sarah, and sends the angel Raphael in disguise to aid them both.

Raphael makes the trip to Media with Tobiah. When Tobiah is attacked by a large fish as he bathes, Raphael orders him to seize it and to remove its gall, heart, and liver because they make "useful medicines." Later, at Raphael's urging, Tobiah marries Sarah, and uses the the fish's heart and liver to drive Asmodeus from the bridal chamber. Returning to Nineveh with his wife and his father's money, Tobiah rubs the fish's gall into his father's eyes and cures them. Finally, Raphael reveals his true identity and returns to heaven. Tobit then utters his beautiful hymn of praise. Before dying, Tobit tells his son to leave Nineveh because God will destroy that wicked city. After Tobiah buries his father and mother, he and his family depart for Media, where he later learns that the destruction of Nineveh has taken place.

The inspired author of the book used the literary form of religious novel (as in Jonah and Judith) for the purpose of instruction and edification. There may have been a historical nucleus around which the story was composed, but this possibility has nothing to do with the teaching of the book. The seemingly historical data-names of kings, cities, etc.-are used merely as vivid details to create interest and charm.

Although the Book of Tobit is usually listed with the historical books, it more correctly stands midway between them and the wisdom literature. It contains numerous maxims like those found in the wisdom books (cf Tobit 4:3-19, 21; 12:6-10; 14:7, 9) as well as the customary sapiential themes: fidelity to the law, the intercessory function of angels, piety toward parents, the purity of marriage, reverence for the dead, and the value of almsgiving, prayer, and fasting. The book makes Tobit a relative of Ahiqar, a hero of ancient Near Eastern folklore.

Written in Aramaic, the original of the book was lost for centuries. The Greek translation, existing in three different recensions, is our primary source. In 1955, fragments of the book in Aramaic and in Hebrew were recovered from Cave IV at Qumran. These texts are in substantial agreement with the Greek recension that has served as the basis for the present translation.
 
 

NOTE:(Explaination taken from the Douay-Rheims Bible web site)

Pope Damasus assembled the first list of books of the Bible at the Roman Council in 382 A.D. He commissioned St.  Jerome to translate the original Greek and Hebrew texts into Latin, which became known as the Latin Vulgate Bible and was declared by the Church to be the only authentic and official version, in 1546.

Tobit is one of the seven Deutero-Canonical books of the Old Testament (erroneously called Apocrypha by Protestants).  These seven books were included in the 1611 King James Version, but not in later KJV Bibles.

St. Jerome considered the seven Deutero-Canonical books to be NOT inspired by God, but he was commissioned by Pope Damasus to translate all 73 books into Latin. Pope Damasus considered the 7 DC books to be inspired by God. Later in 1946, after the finding of the dead-sea scrolls, it was discovered that these 7 DC books were used by the Jews in Alexandria, even in their services. This verifies that Pope Damasus was correct.

It is interesting to note that the Palestinian Jews did not accept the 7 DC books for their version of Holy Scriptures and neither did they accept any of the New Testament. Unfortunately, the King James Bible is based on this version which comes from a people who did not accept Jesus Christ as the Messiah.