When Was the Book of Nehemiah Written?

The events recounted in Nehemiah range from the report of the disrepair of Jerusalem coming to Nehemiah in 445 BC, through his first term as governor of Judea (a period of approximately twelve years), followed by a period of undetermined length during which Nehemiah was presumably back in Persia, and a brief account (chap. 13) of several corrective actions Nehemiah takes in an apparent second term as governor. All told, the events of the book span approximately 15-20 years, bringing its events to a close about 425 BC and the book in its final form before the end of the fifth century BC.