One story, not three
People have been referring to the books as if they are sequels of each other and form a trilogy. Technically that is incorrect because the Lord of the Rings is made up of thee volumes not three parts. When Tolkien first wrote it it was ONE book, but because of it's length and the paper shortages as a result of the war, the publisher had to split it up. It was not Tolkiens intentions for the story to be seen as three seperate parts.