Hobbits first appeared in the 1937 children's novel The Hobbit, whose titular hobbit is the protagonist Bilbo Baggins, who is thrown into an unexpected adventure involving a dragon. In its sequel, The Lord of the Rings, the hobbits Frodo Baggins, Sam Gamgee, Pippin Took, and Merry Brandybuck are primary characters. Hobbits are briefly mentioned in The Silmarillion and Unfinished Tales, which are set in the same fictional world, Middle-earth. The origins of the name hobbit have been debated; literary antecedents include Sinclair Lewis's 1922 novel Babbitt, and Edward Wyke Smith's 1927 The Marvellous Land of Snergs. There is a disputed connection with old names for ghostly creatures, which include boggles, hobbits, and hobgoblins. There is a better substantiated one with rabbit, since Bilbo is repeatedly compared to one in The Hobbit; the Tolkien scholar Tom Shippey identifies five parallels between hobbit and rabbit.