The period of history lasting about 200 years between the time of Joshua and Saul (from about 1200-1000 B.C.) - a time marked by disorder, idolatry and foreign oppression - is known as the reign of the Judges. The time is described: "In those days there was no king in Israel: every man did that which was right in his own eyes." (Judges 21:25.)
The Bible Dictionary in the 1983 LDS edition of the King James Bible (page 719) gives this definition under the entry of the Judges:"The judge was more than a civil officer. He was generally a military leader as well, and his right to lead rested on the fact that in the eyes of the people he was the strongest and best man for the purpose. Faith in God was always the secret of success; but as a rule the judge was more of a fighter than a preacher."
The Book of Judges consists of three parts:
An introduction - chapters 1 and 2, and through verse 6 of chapter 3.
The history of the Twelve Judges, which falls into a succession of periods of rebellion against God, and the oppressions and deliverances by which they were followed - chapter 3, beginning with verse 7, through chapter 16.
Two narratives, which specifically show the tendency to idolatry and lawlessness - chapters 17-21.
The Bible Dictionary (page 720) gives this insight: "The book was compiled long after the events it records; in [chapter] 18:30, there is a reference to the captivity of the ten tribes. The compiler would have had available earlier writings that he worked into his book, e.g., the Song of Deborah, the parable of Jotham, and some of the utterances of Samson. There is much difficulty in deciding the chronology of the period, as the compiler generally gives his figures in round numbers. In some cases the influence of a judge only extended over part of the land, so that two judges might hold office at the same time."