What is the purpose of Judges in the Old Testament?

== == Judges were there to lead and govern the people when there wasn't an actual King to lead the people of Israel.

The Book of Judges covers the period from around the death of Joshua to the period just before the commencement of the Kings. It thus forms a bridge in the history of Israel of about 350 years between the conquest and the monarchy. It shows the cycles of the Israelites departing from God, then being oppressed, crying for deliverance to God who then would send a deliverer, or judge, only for it to be repeated all over again. This is referred to as 'the cycles of the Judges.'

Another theme is repeated twice in Words but demonstrated repeatedly throughout the book:

25In those days there was no king in Israel: every man did that which was right in his own eyes.