The book of Esther is unique in the Old Testament in that it does not once mention the names of God (Yahweh or Elohim). And yet it is highly esteemed among the Jewish people.
The events of the book transpire during the reign of King Xerxes of Persia (present day Iran). The issue was the survival of the Jewish people in Persia. The providence of God is overall evident as a Jewish young woman, Esther, finds herself in a position to save the Jews of Persia from genocide.