The book covers the time between the conquest described in the Book of Joshua and the establishment of a kingdom in the Books of Samuel, during which Biblical judges served as leaders. The stories follow a consistent pattern: the people are unfaithful to HaShem and he therefore delivers them into the hands of their enemies; the people repent and entreat Yahweh for mercy, which he sends in the form of a leader or champion; the judge delivers the People of Israel from oppression and they prosper.
There are Major and minor judges in the book and it is not in chronological order.
The major judges:
Othniel (3:9–11) vs. Chushan-Rishathaim, King of Aram; Israel has 40 years peace until the death of Othniel.
Ehud (3:11–29) vs. Eglon of Moab
Deborah the prophetess and Barak the army leader (4–5), vs. Jabin of Hazor (a city in Canaan) and Sisera, his captain
Gideon (6–8) vs. Midian, Amalek, and the “children of the East”
Abimelech (9) (who is traditionally counted as a king not a judge, and is considered evil) vs. all the Israelites who oppose him