Throughout the book Tolkien has given instances of the corrupting influence of the Ring, which represents power. It seems that everyone who possesses power is ruined by it. Even Saruman, who was once a good wizard, is corrupted by it. And Frodo, who is the hero, finds himself compelled by the Ring. Not only does it weigh on him so much so that he can hardly walk, he is nearly unable to throw it into the volcano.
Gandalf is afraid of the Ring. He has seen first-hand that good people can be ruined by this evil Ring. He refuses to take it when Frodo asks him. Galadriel is the same way; she does not want to be ruined by the power. There are others who seem resistant to the appeal of the Ring. Sam, for instance, seems so good-hearted and pure that though he feels the Ring, he is able to give it back to Frodo and also recognize that it has exerted some pull on his own actions. And Tom Bombadil, like Sam, seems not to be affected by the Ring.
Boromir is an example of a good man who covets the Ring within the action of the novel. He thinks that he can handle the Ring and not be affected by it. But his desperation gives him away. Frodo realizes that he cannot even trust his friends, because the Ring exerts a force on even the best of men.
The Ring, which is synonymous with power, hold attraction for many, but none can possess it. The Ring itself cannot be controlled or tamed. The irony of the title is obvious: there can never be a "lord" of the Ring.
The Lord of the Rings is a classic struggle between good and evil. This universal theme is obvious as Frodo seeks to destroy Evil, and Evil seeks to destroy Frodo. There are many pairs of characters representing good and evil: Saruman and Gandalf, and Sauron and Tom Bombadil.
There are also characters whose very selves are split between good and evil: Boromir, Gollum, and Denethor.
In the end of the novel, Evil is not defeated for good, since Morgoth still lives. But Evil has been defeated by Good; that is the most important battle in the novel.
In accordance with the Christian faith, the characters of Tolkien's novel are altruistic. There are many instances of altruistic behavior, of which Sam's stands out. Though he sets out with extremely romantic ideas his quest turns out to be one that is life threatening. At great personal cost Sam accompanies Frodo making sure that the Ring-bearer is not lacking in anything. Sam himself goes without food and drink to make sure that Frodo has enough; he even goes without sleep so that Frodo may sleep peacefully and safely. Frodo himself makes a great sacrifice. He gives up his comfortable life in the Shire to go on the quest and make life easier for the Shire folk, most of whom are ignorant of his sacrifice and his deeds.
Aragorn, one of the greatest characters of The Lord of the Rings, does things quietly and with much thought. He roams Middle-earth gathering information that will aid the Ring bearer in his quest. He does this without revealing his true identity and even posts his men, the rangers around the Shire, to protect its people. He does his duty to his ancestors. He reforges the Sword Anduril and gives the Dead a chance to redeem themselves. He is a good king, who looks to the interests of his people and does not try to grab opportunities unscrupulously. Arwen gives up her right to immortality so that she may marry Aragorn. She lets Frodo go to the Blessed Realm instead of herself, and Frodo rightly deserves the honor.
The Ents know that their end is near. They cannot find Ent wives and they know their race is doomed. Yet, they spend their precious lives and time on the storming of Isengard. Their sense of responsibility is great, as is that of Faramir and Boromir. These two brothers try to do their father's bidding: Boromir goes to Rivendell to get help from Elrond while Faramir goes to Osgiliath to protect the borders of Minas Tirith, even though he knows that is a fatal task.
Tolkien has stressed the importance of altruism and responsibility. The god characters always manage to do their duty even if it is at the cost of one's life. They know that a greater good is served by their individual sacrifice.
Middle-earth is a creation of Tolkien's imagination. It is peopled by many creatures of different groups. All these creatures have their own social and moral codes that correspond to their groups. However different they may be from each other, they understand the value of peace and harmony.
One of Tolkien's themes is the importance of racial harmony. This is epitomized by the friendship between Legolas the Elf and Gimli, the Dwarf. This friendship represents and ideal. Interestingly, the races of Middle-earth remain separate for much of the novel. But when the War of the Rings begins, they come together as a united front. This is Tolkien's vision.
Tolkien's Middle-earth is not covertly Christian, but as Paul Kocher remarks "it contains many of the transcendent elements of a more than pantheistic religion." There is an underlying scheme of values and rituals of religion and the emphasis placed on pity and forgiveness is definitely Christian. There are examples of sacrifice and redemption, as well as forgiveness and rebirth. These religious themes lend authenticity to the imaginary world of Middle-earth.
Tolkien has invented not only names but also languages for the different races of Middle-earth. The Elves speak a language that is soft and pleasant sounding; the orcs, on the other hand, have a language that is just as bad as their behavior.
Tolkien's attention to detail is remarkable. With each change in status, the characters are given new names. Strider becomes Aragorn who then is crowned king Elessar. Tom Bombadil has many names and is called different names by different races. Even the speeches or talking style of the characters in different. Treebeard the Ent, who is the oldest living thing on Middle-earth, talks in long sentences. The Hobbits, on the other hand, are short and to the point in their speech.