Lord of the Rings
The Lord of the Rings is a series of novels written by J.R.R. Tolkien as an extension to his children's novel, "The Hobbit". The Lord of the Rings represented Tolkien's desire to make a full length book. In the Lord of the Rings (and in The Hobbit) Tolkien describes a detailed world, which he calls "Middle Earth", which includes common fantasy races Elves, Dwarves and Humans living in harmony and opposed to common fantasy evil races orcs, goblins and trolls. Tolkien, however, also presented a new race, the hobbit, which was a generally good, but supposedly barely noticed, race with large hair covered feet that was somehow able to have wonderful talents. The aim of the story was to try to show to children that no matter how useless they might feel, they, like the hobbit, could prove to be able to make a big difference. There were also various lesser morals to the story as well.
The story focuses around a ring. In "The Hobbit", the ring was simply able to make someone invisible. In The Lord of The Rings, the ring had a more sinister use, with the ability to control evil, and hence it had an evil aspect to it. The aim of the entire story was to destroy the ring. Everything surrounding the story, with so many great and wonderful things, surrounded destroying the ring.
Like with many other epics, the Lord of the Rings used many aspects that are already familiar to many readers - most of the races (aside from Hobbits), many of the mythos and many of the accepted truths were all copied from other works. They then introduced new aspects, such as the Hobbit, but also lesser characters such as the walking trees. They then created a deep explanation for these races and for the entire situation, which roughly agreed with other established mythos, but went deeper.
Tolkien's stories were loosely based on historical research into Norse mythology, although he combined these with other mythos. Originally, Tolkien had used Fairies instead of Elves, but changed this towards the end of the writing process.
Many other books have been published that explain Tolkien's writing process, and the greater story behind the Lord of the Rings world, including the various gods, and how the evil person behind everything was in fact a God that was sent down to earth as a mortal as punishment for trying to do too much.
The Lord of the Rings was loved so much by so many people because of its consistency. Everything made sense and stood up to deep analysis. There were holes, of course, and people deeply involved in the story went to pains to try to prove them. Like Star Trek, however, they were few and took a real student of the work to find them.