The LOTR trilogys, and Tolkiens books, are incredible. If you google/look up my user name, you will see that I am, indeed, a HUGE LOTR fan, lol.
As mentioned above, Tolkien was a linguist, and invented many beautiful languages, including Elvish. His "works" started by first inventing certain languages, and then, in turn, wanting to create a "world" for these languages to be spoken in.
Tolkien started penning his stories while in the trenches of WW1. In fact, his "visions" of the evil land of Mordor, with its burnt, and destroyed landscape, were based on the battlefields of WW1, and the "no mans land" in between the German and British trenches.
To me personally, the beauty of Tolkiens work, is how not only was it an incredible, rich, vibrant "fantasy" story, but he wrote it as though it was real history. History of our world from an ancient, era, or epoch, of a long ago forgotten past. He mixed, fantasy writing, historical context, mythology, and linguistics, PERFECTLY together.
In many circles, he is known as the "master", and once you read his books, you can quickly understand why. If you are a fan of the movies, you will LOVE the books as well.