The Hobbit by John R. R. Tolkien

The Hobbit is a fantasy novel and children's book by John R. R. Tolkien: Gandalf tricks Bilbo into hosting a party for Thorin and his band of dwarves, who sing of reclaiming the Lonely Mountain and its vast treasure from the dragon Smaug. When the music ends, Gandalf unveils a map showing a secret door into the Mountain and proposes that the dumbfounded Bilbo serve as the expedition's "burglar". The dwarves ridicule the idea, but Bilbo, indignant, joins despite himself.
The group travel into the wild, where Gandalf saves the company from trolls and leads them to Rivendell, where Elrond reveals more secrets from the map. Passing over the Misty Mountains, they are caught by goblins and driven deep underground. Although Gandalf rescues them, Bilbo gets separated from the others as they flee the goblins. Lost in the goblin tunnels, he stumbles across a mysterious ring and then encounters Gollum, who engages him in a game of riddles. As a reward for solving all riddles Gollum will show him the path out of the tunnels, but if Bilbo fails, his life will be forfeit. With the help of the ring, which confers invisibility, Bilbo escapes and rejoins the dwarves, improving his reputation with them. The goblins and Wargs give chase but the company are saved by eagles before resting in the house of Beorn.
The company enter the black forest of Mirkwood without Gandalf. In Mirkwood, Bilbo first saves the dwarves from giant spiders and then from the dungeons of the Wood-elves. Nearing the Lonely Mountain, the travellers are welcomed by the human inhabitants of Lake-town, who hope the dwarves will fulfil prophecies of Smaug's demise ... (Summary by Wikipedia)