Eli was the main priest. Samuel was born to Hannah, a barren woman, after she prayed to God and Eli also asked God to help her. Samuel was dedicated, by his mother, to God. At one point, the Ark of God was taken by the Philistines, causing their idol Dagon to fall and be disgraced (1 Samuel 5). Samuel became judge of Israel (1 Samuel 7) when Israel defeated the Philistines at Mizpah, at a place that Samuel named Ebenezer (meaning "the Stone of Help"). The people insisted on having a king. Samuel finally picked Saul, the tallest man (1 Samuel 9:2), who was made king at Gilgal (1 Samuel 11:15). Saul made a mistake of personally making a burnt offering instead of letting Samuel do it, thus requiring his dynasty to end (1 Samuel 13:9; 12-14).
David and Goliath (1 Samuel 16, 17):
A young shepherd, David, was brave, strong, and favored with the Lord. David played the harp for king Saul when Saul had the "Spirit from the Lord" tormenting him. Goliath was a champion of the Philistines, a giant over nine feet tall. Goliath challenged for the battle of the Philistines and Hebrews to be a single combat of one Israelite and him. David accepted the challenge and killed Goliath with a sling and a stone thrown to Goliath's head. (1 Samuel 17:48-51).
David became well known and was honored with a song (1 Samuel 18:7), "Saul has slain his thousands, and David his tens of thousands," which made king Saul very angry. David became a "blood brother" to Jonathan, king Saul's son, and married Michal, king Saul's daughter. Saul decided to kill David and pursued him over the land. Twice (1 Samuel 24; 1 Samuel 26), David spared Saul, when David could have easily killed him. Saul consulted a medium at Endor (1 Samuel 28). On Mt. Gilboa, Saul was wounded by the Philistines. Saul killed himself and was cremated. (1 Samuel 31:12).