What changed between the books and the show?

How closely did the early seasons follow the novels?

Closely enough that the first seasons work as a rough guide to the first books. The original plan was for each novel to supply about a season of television, and for a while that structure held. What changes is the texture. A long novel has to be cut to ten hours of screen time, so whole chapters of travel, rumour and minor lordship fall away, and the scenes that survive carry more of the story than they did on the page.

The deeper change is one of form. Each chapter of the novels is told from inside a single point-of-view character, so readers learn what someone is thinking at the moment they act, and much of what matters in the books is a character misreading a situation. A camera can only show behaviour. The series therefore invents conversations, confrontations and confessions to put on screen what the books leave inside a character's head, and those additions are where the two versions first begin to drift apart.

Why does the show rename and reshape characters?

Mostly for the viewer's ear and eye. A reader can flip back a hundred pages to check which of two similar names is which; a viewer meets a face and a name once and has to keep up. Asha Greyjoy is the clearest case: the series called her Yara from her first appearance in the second season, reportedly to avoid confusion with Osha, a wildling woman whose name would have sounded almost the same on screen.

Reshaping goes further than renaming. With a cast this large, a television series has every reason to give one actor the job of two characters, to move a plot from one region to another so that it crosses a storyline viewers already follow, and to bring a confrontation forward because a season needs a climax. None of that means the show disregarded the books. It means the show had different problems to solve, and its answers to them gradually became a separate version of the story.

What happened when the series ran past the books?

When Game of Thrones began in April of its first year on air, four of the novels were in print; A Dance with Dragons, the fifth, followed that July. Five books comfortably covered the first half of the series, but by the sixth season the show had overtaken everything published and was telling parts of the story readers had never seen. From then on the comparison runs the other way: the books are the version still to come.

Martin's own hand on the screenplays was concentrated early. He scripted one episode a season for the first four, and the two showrunners, D. B. Weiss and David Benioff, wrote most of the rest themselves. That division matters to how the later seasons are judged: the further the show travelled beyond the books, the more its choices were the showrunners' own, and the more viewers' arguments about the ending became arguments about adaptation.

Will the books end the same way as the show?

No one outside the author can say. The Winds of Winter, due to be the sixth novel, is unpublished as of the date this page was last checked, as is the seventh, A Dream of Spring, and this page makes no prediction about when either will appear. What can be said is that the two versions have already parted company in many places, so even where the destinations prove the same, the routes will differ.

The most likely shape of the difference follows from the form. Because the novels can stay inside a character's head, they can make a decision that feels abrupt on screen seem gradual and earned on the page. That is the main reason readers who disliked the final season still expect to find the books more convincing: not because the events must change, but because the reasoning behind them will be shown at the length the books always give it.