The television series Game of Thrones, produced by HBO, is broadly based on the series of fantasy novels "A Song of Ice and Fire" written by George R.R. Martin. For the most part, the earlier seasons kept quite accurate to the books, with some deviations. For instance, the first season of Game of Thrones aligns closely with the events of the first book, "A Game of Thrones". However, as the series progressed, the showrunners David Benioff and D. B. Weiss started to take creative liberties, introducing, omitting or changing various plot lines and characters to cater to the television medium. The storytelling, therefore, began to deviate significantly from the original source, especially in the later seasons. A few of the key differences without revealing major spoilers include: - Character Arcs: Some character arcs in the series are significantly different or more developed in the books than in the TV series. For instance, the arcs of Stannis Baratheon and Ser Barristan Selmy differ quite extensively in the books as compared to the series. - Missing Characters: There are also characters present in the books that have been completely omitted from the series such as Lady Stoneheart, Arianne Martell, and Young Griff. - Different Outcomes: There are also several outcomes and events in the TV series which differ from the books. One notable example is the fate of Sansa Stark in the latest seasons. It is important to note, however, that the books have not been completed yet. The last two books - "The Winds of Winter" and "A Dream of Spring" - are yet uncompleted and unpublished, which means the TV series had to develop its own conclusions, particularly for the final seasons. So if you enjoyed the television series and are interested in a richer exploration of the world and characters, you will definitely find much more in the books, including detailed backstories, inner monologues, and additional plot lines. Be prepared however for the differences and the as-yet unresolved storyline in the books!