There are some interesting idiosyncrasies in the book of Judges that would lead us to question who actually wrote it.
We receive one clue from the words found at Judges 1:21, where we read:
‘Nor did the children of BenJamin take JeruSalem from the Jebusites as their inheritance;
So, the Jebusites still live among the children of BenJamin in JeruSalem to this day.’
Then we read at Judges 18:1:
‘There was no king over IsraEl back then.’
Therefore, whoever did the writing must have lived during the time when a king ruled IsraEl, but before the kings started ruling in JeruSalem and/or possibly during the reign of Saul.
Thus, the prophet SamuEl seems to be the likely source.
However, notice the apparent contradiction found at Judges 18:30, where we read:
‘And JoNathan (the son of Gerson and grandson of ManasSeh) and his sons became the Priests of the tribe of Dan until the time when the nation was captured and carried away [into captivity].’
These words would then indicate that at least portions of the book were written sometime after IsraEl’s conquest by the Assyrians, and possibly as late 6th Century BCE.
So, how do we resolve those differences?
We can see from the context that the book of Judges was written close to the time of the Judges (perhaps by SamuEl).
Then it appears as though a later copyist (perhaps Ezra) added the comment at Judges 18:30.
And since this comment is found both in the Hebrew and Greek texts;
We know that it had to have been written sometime before the 3rd Century BCE.
Also notice that the surrounding books of Joshua and Ruth are clearly just a continuation of the same writing, for where one leaves off, the next begins.
So, it seems as though the transcribing of these other Bible books date to the same period.