The Return of the King by J.R.R. Tolkien has many different themes in it. One of my favorite themes in the book is to have courage, and to never give up hope. This theme is conveyed very well in chapter 6, The Battle of the Pelennor Fields.
In this chapter, there is an extraordinary battle between good and evil to decide the outcome of Minas Tirith (the city above the Pelennor Fields), and the rest of Middle-earth. During the battle, Prince Éomer of the Mark (Also called the men of Rohan, an empire beyond Minas Tirith) was fighting hard, and it looked as if the humans would lose the battle against the evil orcs and goblins. Then, from the sea beside them came some ships, but they were of the Enemy. Although, the situation looked totally hopeless, Éomer continued to fight hard.
"Stern now was Éomers mood, and his mind clear again. He let blow the horns to rally all men to his banner that could come thither; for he thought to make a great shield-wall at the last, and stand, and fight there on foot till he fell, and do deeds of song on the fields of Pelennor, though no man should be left in the West to remember the King of the Mark. So he rode to a green hillock and there set his banner, and the white horse ran rippling in the wind." Pg. 137
After he regained the courage of his men and his own, he began to fight again, and his courage was rewarded.
"And he lifted up his sword to defy them. And then wonder took him, and a great joy; and he cast his sword up in the sunlight and sang as he caught it. And all eyes followed his gaze, and behold! Upon the foremost ship a great standard broke, and the wind displayed it as she turned towards the Harlond. There flowered a White Tree, and that was for Gondor" pg. 137
Gondor was part of their kingdom, and the tides had turned. If Éomer and his men had given up, they may not have lived to see their great allies come to save them.
I believe this chapter conveys the ideal of courage manifested by Éomers resolve to never give up. The ideals expressed in this fantasy novel are easily applied to situations in real life. No matter how enormous the opposition is, there is always hope for victory.