The Twilight Saga, written by Stephenie Meyer, consists of four books centered around the love story between a human girl, Bella Swan, and a vampire, Edward Cullen, set against a backdrop of supernatural beings like vampires and werewolves. Key characters include Bella, Edward, Jacob (the werewolf who loves Bella), and members of the Cullen family, each possessing unique abilities and backgrounds. The series explores themes of love and conflict between different supernatural entities.