Most people have made this mistake of thinking Middle-earth is a particular kind of earth or is another planet of the science fiction sort but it's just an old fashioned word for this world we live in, as imagined surrounded by the Ocean.

The Nazgul they were; the Ringwraiths, the Enemy's most terribly servants; darkness went with them and they cried with the voices of death.

All my own small perception of beauty both in majesty and simplicity is founded.

But Sauron was not of mortal flesh, and though he was robbed now of that shape in which had wrought so great an evil, so that he could never again appear fair to the eyes of Men, yet his spirit arose out of the deep and passed as a shadow and a black wind over the sea, and came back to Middle-earth and to Mordor that was his home. There he took up again his great Ring in Barad-dur, and dwelt there, dark and silent, until he wrought himself a new guise, an image of malice and hatred made visible; and the Eye of Sauron the Terrible few could endure.

People remember Longfellow wrote Hiawatha, quite forget he was a Professor of Modern Languages!

Don't put a lump of rock under my elbow again!

Have you thought of an ending?' 'Yes , several, and all are dark and unpleasant,' said Frodo. 'Oh , that won't do!' said Bilbo. 'Books ought to have good endings. How would this do: and they all settled down and lived together happily ever after?' 'It will do well, if it ever comes to that,' said Frodo.