Samuel, The Old testament

It is in the Books of Samuel that we see some prominent leaders in a more complete way, with both their virtues and their weaknesses. It all starts with a woman, Hannah, who is sad because she has not had a child. She takes her problem to Eli, priest of the Tabernacle, who first takes her for a drunken woman. When he understands Hannah's plight, he promises that her wish will be fulfilled. She, in turn, promises to dedicate the child to the service of the Lord.
Samuel is the child promised by Eli. True to her word, Hannah brings the little boy to the tabernacle as an offering to God as soon as he is weaned. He serves under Eli, a wise and kind man with a large problem. His sons assist him at the tabernacle, but misuse their office in the worst ways imaginable. Eli is not ignorant of their sins, but lacks the courage to act decisively. Finally, God chooses little Samuel to deliver His message to Eli: both Eli and his sons are doomed to destruction as a consequence of the sons' misuse of religious authority.
The grim sentence is carried out, and it becomes understood that it is Samuel who will take over the role of priest in the Tabernacle and as the Judge of Israel. Samuel grows into these two roles and fills them admirably.  
But another problem arises. The people are dissatisfied, not with Samuel, but with the loose system of leadership given to Israel by the Judges. They now want to be like other nations - with a king. God answers Samuel's inquiry on the matter by saying that having a king is a bad idea, but He also counsels Samuel to let the people have their way, because they just might learn from the consequences. A tall young man from the tribe of Benjamin, Saul, is chosen for the job.   
Saul serves as king for a long time, but Samuel is always near. His role now seems to be more like second guesser in chief. Saul develops, over the years, a condition that we might now describe as bipolar or paranoia. His final break with Samuel comes when the Israelite army fails, though they have the ability, to carry out the divinely commanded slaughter of the Amorites and their livestock. Their king's life is spared in hopes of generating a ransom. Samuel sees that God's command has not been fulfilled, and he becomes furious enough to hack the Amorite king to pieces with an ax. He then leaves to find Israel a new king.
The king to be is David, the son of Jesse, of the tribe of Judah. It is some time before David actually takes office. In the meantime, his relationship to Saul is very complicated, but Samuel, now aged, never reverses his anointing David as the next Israelite king. Samuel finally passes on, and a new prophet, Nathan, assumes the calling of David's connection to God.