The fictional races and peoples that appear in J. R. R. Tolkien's fantasy world of Middle-earth include the seven listed in Appendix F of The Lord of the Rings: Elves, Men, Dwarves, Hobbits, Ents, Orcs and Trolls, as well as spirits such as the Valar and Maiar. Other beings of Middle-earth are of unclear nature such as Tom Bombadil and his wife Goldberry.
Wizards like Gandalf were Maiar but took the form of Men.
Smaug in fan art
Middle-earth is the setting of much of the English writer J. R. R. Tolkien's fantasy. The term is equivalent to the Miðgarðr of Norse mythology and Middangeard in Old English works, including Beowulf. Middle-earth is the human-inhabited world, that is, the central continent of the Earth, in Tolkien's imagined mythological past. Tolkien's most widely read works, The Hobbit and The Lord of the Rings, are set entirely in Middle-earth. "Middle-earth" has also become a short-hand term for Tolkien's legendarium, his large body of fantasy writings, and for the entirety of his fictional world.
A detail of Middle-earth in one of Peter Jackson's film sets
Medieval Christian cosmology: heaven above, earth in the middle, hell below. Vank Cathedral, Isfahan.