Like its prototype, the story and song of Deborah (Judg. 4-5), Judith carries a message of faith in the deliverance of God’s people in the face of political and military oppression. In particular, the feminism of the book is deliberate. The point seems to be not so much that God chooses a woman to prove his strength—Judith is no weakling—but that a woman is the appropriate instrument of a God who is the helper of the oppressed (9:11). Judith may be also a personification of ‘Judea’ and, in her final song of triumph, speak as the mother of the Jewish people.
The story has had an influence on Western literature and art. It was one of the two apocryphal books with sufficient popularity in the West to convince Jerome to include it in his Vulgate translation of the Bible. For Catholics, it is one of the deuterocanonical books, while, for Protestants, it is included among the Apocrypha. (Harper's Bible Commentary)