Judges takes place roughly between 1250-1050 BC. The last judge in this book is Samuel, after which the nation of Israel chooses to be led by King Saul. Tribal loyalty replaced national unity as the children of Israel formed a loose confederation of tribes.
This description of the book from the institute student manual is helpful:
When Joshua and the leaders of Israel who served under him died, the national spirit of Israel also died. Tribal loyalty replaced national unity. Each tribe began to look to its own resources without giving help or asking aid from their fellow Israelites. Joshua’s generation remained faithful to the Lord (see Joshua 24:31), but spiritual apostasy soon occurred in the following generation.
“And there arose another generation after them, which knew not the Lord, nor yet the works which he had done for Israel…And they forsook the Lord God of their fathers, which brought them out of the land of Egypt, and followed other gods, of the gods of the people that were round about them, and bowed themselves unto them, and provoked the Lord to anger.” (Judges 2:10, 12.)
None of this apostasy needed to happen. The Lord had directed Israel into the promised land and had provided them with a political covenant. He was to be their divine sovereign. Their temporal leaders were to be ruling judges, under whom the people retained religious and political liberties. (Such a form of government was advocated in the Book of Mormon by King Mosiah [see Mosiah 29].)
Israel’s political covenant showed the mercy and long-suffering of the Lord and would have been the best possible government in Israel. As can be seen in both the Bible and the Book of Mormon, however, under the rule of the judges the people must demonstrate loyalty to the Lord and His commandments for this ideal form of government to function properly. Since Israel usually broke their covenant during the reign of the judges, the governmental system did not function properly, and Israel fell out of favor with the Lord. The reign of the judges is similar in many ways to the history of the Nephites prior to the coming of Christ. It is a story of one continuous cycle of apostasy and repentance. When the Israelites turned from the Lord, their enemies began to prevail (see Judges 2:14–15).
Suffering under oppression and war, the people would cry unto God and He would raise up a Deborah or a Gideon to deliver them. But once peace and security were reestablished, the people turned again to their former ways (see Judges 2:16–19). (Old Testament Institute Student Manual, p. 251)
The story of the time of the book of Judges is mainly a heartbreaking and disastrous one, although in this period some of the most amazing stories of faith and hope occur. Judges contains accounts of some remarkable men and women who, against all odds, show that faith in the Lord pays dividends. In their lives of courage and faith are many relevant principles which the youth of the world can learn to live by.
With the time we have in class to cover this book, I chose to emphasize the cycle of apostasy and repentance contained in the book of Judges, the accounts of Ehud (Judges 3), Deborah and Jael (Judges 4-5), Gideon (Judges 6-8), and Samson (Judges 13-16). Occasionally I am asked about the sacrifice of Jepthah’s daughter in Judges 11. We will look at that account and see what lessons it teaches us today.
Great little lesson from Jepthah at http://oldtestament.byu.edu/spotTaylorHalverson.php (see the 2nd to last question on the page.)