Apple has released an enhanced ebook of George R.R. Martin’s best-selling original “Game of Thrones” novel under an exclusive pact with Random House, which includes an excerpt from the forthcoming sixth book in the series, “The Winds of Winter.”

“A Game of Thrones: Enhanced Edition” is available exclusively on Apple’s iBooks for $8.99. The company also is offering pre-orders of the enhanced editions of books 2-5 in Martin’s “A Song of Ice and Fire” series for $11.99; those will be released over the next few months.

Fans will be treated to additional content from the book, including a deeper history of some of the great houses of Westeros, summaries of the 92 sigils and family trees, glossaries, interactive character maps, and detailed annotations. The ebook also features new covers and illustrations, along with audio clips narrated by actor Roy Dotrice (who portrayed alchemist Hallyne in season 2 of HBO’s “Game of Thrones”).

“We’re now entering a new period in the history of publishing,” Martin said in a statement. “The digital book gives readers the ability to experience all this rich secondary material that had not been possible before. Anything that confuses you, anything you want to know more about, it’s right there at your fingertips. It’s an amazing next step in the world of books.”

Eddy Cue, Apple’s senior VP of internet software and services, added, “‘A Game of Thrones: Enhanced Edition’ is one of the absolute best enhanced books ever offered on iBooks. Both newcomers and longtime fans are going to love immersing themselves in this epic novel and interacting with all the bonus material.”

HBO’s “Game of Thrones” season 6 aired earlier this summer, and the storylines have already overtaken Martin’s books. The seventh season is slated to hit HBO in the summer of 2017, and the premium cabler has said season 8 will be the final installment.