In a 1955 letter to W. H. Auden, Tolkien recollects that he began work on The Hobbit one day early in the 1930s, when he was marking School Certificate papers. He found a blank page. Suddenly inspired, he wrote the words, "In a hole in the ground there lived a hobbit."

Bilbo's ancestry is somewhat noble by hobbit standards: his father was from the well-to-do, conventional Baggins family, but his mother was from the Tooks, a wealthy, eccentric family infamous for their unhobbitlike tendency to go on adventures.

Gandalf tricks Bilbo into hosting a party for the band of dwarves, who clean out Bilbo's pantry before settling down to discuss business.

Sting is an ancient Elvish blade made by weapon-smiths in Gondolin. When Orcs or goblins are within an undetermined radius, the blade glows blue, alerting Bilbo to their presence.

The Third Age was the Age of Arda that lasted for 3021 years, from the first defeat of Sauron by the forces of the Last Alliance and the deaths of Elendil and Gil-galad, to the departure of Gandalf, Galadriel, Elrond, Bilbo, and Frodo to the Undying Lands after Sauron's final downfall during the War of the Ring.

Thorin Oakenshield is leader of the company and possessor of the longest beard.

Smaug is a fearsome dragon who invaded the Dwarf kingdom of Erebor 150 years prior to the events described in the novel. He is depicted by Tolkien as an intelligent being capable of speech, easily pleased by flattery and fascinated by Bilbo's description of himself in riddles.

When the trolls are arguing over whether/how to kill Bilbo and the dwarves, Gandalf chimes in (out-of-sight), sounding like one of the other trolls. He does this repeatedly, because he knows that if he can keep them arguing, the sun will come up and they will turn to stone from whence they came.

Until he finds the magic ring, Bilbo is more baggage than help.

Gollum survives on cave fish, which he catches from his small boat, and small goblins who stray too far from the stronghold of the Great Goblin.