LOTR: What Is The Difference Between Middle Earth, Arda, And Beleriand?

The lore surrounding The Lord of the Rings is so expansive that it can sometimes be difficult to keep up with. The world Tolkien created is so detailed that there are many places that the story never even visits, but they are still important to the world at large. The lore goes deep enough that there is a whole mythology surrounding the creation of the world and the extended history of Middle-earth, and because it is secondary to the story, often only the most die-hard fans even know about it.