The Lord of the Rings Online Lorebook has been updated with a profile on old Tom Bombadil, that merry fellow in the yellow boots.
This verse describes the surface appearance of the strange entity known as Bombadil. He seems a jovial (if not somewhat absurd) fellow, skipping and singing through the treacherous Old Forest at the Bounds of Buckland; but beneath the surface is hidden a Power that few, even the Wise, can comprehend. He is old beyond the count of years - indeed, the Elves once called him Iarwain Ben-adar, Oldest and Fatherless - and once leapt upon the hilltops across the wide lands of Middle-earth. Now, though, he has settled in the Old Forest with his wife Goldberry the River-daughter, and set for himself unseen bounds which he no longer crosses.
Within those bounds, Tom is the Master - not that he claims ownership or lordship over anything or anyone within those bounds, but that he is his own master, and no one has ever caught him unawares. He has at times displayed the power to cast down barrow-wights and master the wiles of the dangerous Old Forest, as well as calming mighty Old Man Willow and resisting the corrupting power of the One Ring as though it were but a worthless trinket. Those wandering in the Old Forest would do well to seek refuge with Old Tom, or they might find themselves at the mercy of the waking trees.
;)
Read more about Tom Bombadil here.
