A formgeschichtlich study of the Hebrew and Aramaic letters of the Old Testament and its environment (9th century BCE to 2nd century CE) presenting a history of the genre of the northwest Semitic epistolary form, including the Babylonian-Assyrian, demotic and Greek epistolary form of the first millennium, as well as a form criticism of the Aramaic letters of the book of Ezra (the question of authenticity).