EDIT: One thing I should add is that the show often makes things explicit which, in the books, are only hinted at or revealed over time. This happens as early as the first two seasons, in which much of ambiguity behind characters like Littlefinger and Margaery Tyrell are stripped away.
While Game of Thrones and House of the Dragon are inspired by Martin's writing, fans know how much the shows deviate from the books. Jon Snow is a perfect example of such changes. As perhaps the most central character in Game of Thrones and Martin's novels, there are some key differences between these two versions of Jon Snow.

The most glaring difference is that fact that Euron in the book wears an eye patch, earning him the nickname Crow's Eye. 9. His Brothers. As far as the show has confirmed, Euron is the only brother of Balon Greyjoy and thus has only Yara to contend with when Salt Throne becomes available.

The following is a list of differences between Season 2 of the television show House of the Dragon and Fire & Blood, the book from which it is adapted. Unlike Game of Thrones, this TV series is based on a series of prequel novellas (collected in Fire & Blood) which are written as in-universe history books, not fully narrativized; as such they are outlines, and the TV series will have to fill
The differences between the HBO show and Martin’s books began long before reaching the final season of Game of Thrones.Martin refers to it as a “butterfly effect”, noting that the changes or omissions made by the television series may at first seem minor, but they could have a major impact on the story later on. A Game of Thrones - Season 1. A Clash of Kings - Season 2. A Storm of Swords - Season 3 and 4. A Feast for Crows - Season 5 & 6 (Mostly 5) A Dance With Dragons - Season 5 & 6 (Mostly 5) But the last two books are almost completely different from the show. 9. JnBg. 137 241 350 63 304 196 14 126 292

differences between game of thrones book and show