The book series that features a dragon named Smaug is "The Hobbit," written by J.R.R. Tolkien. Published in 1937, "The Hobbit" follows the adventures of Bilbo Baggins, a hobbit who unexpectedly embarks on a quest with a group of dwarves to reclaim their homeland from the dragon Smaug. Smaug is depicted as a cunning and powerful creature who hoards treasures and plays a pivotal role in the story. This fantasy novel has become a classic, inspiring adaptations in film and literature, while highlighting themes of bravery, friendship, and the transformative power of adventure.