Stephenie Meyer's 2005 novel that introduced Edward Cullen was Twilight.
Twilight is the first novel in Meyer's Twilight series, a young-adult fantasy romance centered on seventeen-year-old Bella Swan. After Bella moves from Phoenix, Arizona, to the rainy town of Forks, Washington, she becomes fascinated by Edward Cullen, a mysterious student who is revealed to be a vampire. Edward's family and supernatural identity form the foundation for the series' central conflict.
The novel was published in hardcover on October 5, 2005, by Little, Brown and Company. Meyer reportedly developed the story after imagining a conversation between an ordinary girl and an unusually beautiful vampire. The book's success led to three main sequels: New Moon in 2006, Eclipse in 2007, and Breaking Dawn in 2008.
Readers sometimes select New Moon, Eclipse, or Breaking Dawn because those books continue Edward and Bella's story. However, each is a sequel. Twilight is the book that first introduces Edward Cullen, Bella Swan, and the wider supernatural world of Forks.