Who is Tom Bombadil? Nobody knows for sure, but there are a few commonly accepted possibilities:
- He is one of the Maiar. The reasoning being that this is the most convenient pigeonhole in which to place him (and Goldberry as well). Most of the other individuals in LotR with "mysterious" origins: Gandalf, Sauron, Wizards, and Balrogs did in fact turn out to be Maiar.
- He is Ilúvatar (AKA Eru). Goldberry makes one comment to Frodo that gives this possibility hope: (F: "Who is Tom Bombadil?" G: "He is."). To many this sounds like what God told Moses at the burning bush: "I am that I am." It's a fun thought.
- He is Aulë (one of the Valar). Tom's actions mesh nicely with Aulë's, and to an even greater extent, Goldberry's with Yavanna's (Yavanna is Aulë's spouse). In Goldberry's case, the two are even given a similar physical description.
- He is just Tom, a one-of-a-kind being. Tolkien indirectly supported this idea in his letters: "As a story, I think it is good that there should be a lot of things unexplained ... Tom Bombadil is one (intentionally)."