This is what happens when you wait six years for a book and the book before didn't even have these people in it. I last read about what happened to most of these people nine years ago. I'm 100 pages in and find myself saying, "Oh, Sam helped Bran get across the Wall...but what the hell happened there? I remember he killed an Other, but that wasn't related, was it?" Then I say, "I remember Tyrion killed Tywin, but how exactly did Joff die again?" Some things I could look up on wikipedia quickly (Joff was poisoned, oh yeah, now I'm sort of remembering). But then I say, "Jon Snow hates Slynt and what is the history on that? I can't remember anymore."

Is there a short summary of what's happened in the previous books? Some things, like the Red Wedding, are memorable. But other things - like just who did what little act of treachery against whom - are things that I have long forgotten.