George R.R. Martin has a plan for keeping the Game of Thrones TV show from catching up to the books:
They know certain things. I’ve told them certain things. So they have some knowledge, but the devil is in the details. I can give them the broad strokes of what I intend to write, but the details aren’t there yet. I’m hopeful that I can not let them catch up with me. The season that’s about to debut covers the second half of the third book. The third book [A Storm of Swords] was so long that it had to be split into two. But there are two more books beyond that, A Feast for Crowsand A Dance With Dragons. A Dance With Dragons is itself a book that’s as big as A Storm of Swords. So there’s potentially three more seasons there, between Feast and Dance, if they split into two the way they did [with Storms]. Now, Feast and Dance take place simultaneously. So you can’t do Feast and then Dance the way I did. You can combine them and do it chronologically. And it’s my hope that they’ll do it that way and then, long before they catch up with me, I’ll have published The Winds of Winter, which’ll give me another couple years. It might be tight on the last book, A Dream of Spring, as they juggernaut forward.