AS IMPRESSIVE AS Martin’s universe is, his fans’ engagement with it is perhaps even more so. In the science fiction and fantasy (SFF) community, people often refer to fanac (short for fan activity), which takes many forms: cosplay (costume play), fan art, fan fiction, even filk — a musical genre comprising original songs, parodies and covers — all shared and celebrated at local meet-ups or regional and national conventions. Technology has increased the number of venues, including podcasts, wikis, websites and message boards, for nerding out over a particular topic or piece of arcana, which previously may have occurred only in the back of a bookstore or game shop and now takes place largely online. In Martin’s case, this fanac seems to be in a permanent state of frenzy: The fan-maintained westeros.org has become the foremost clearinghouse of information about his world; the process of readers attempting to predict the release of the next book in the series has its own name — Martinology, practitioners of which include the political analysis site FiveThirtyEight — and Martin himself journals regularly on his so-called Not a Blog at his eponymous website, where he ends each post with a description of his mood: melancholy, say, or bouncy. All told, it’s possible that more has been written about the fictional kingdoms of Westeros than about some actual countries on earth.

This conversation sometimes takes place in real time but also continues for years and decades — in the long wait between books (seven years after the last book, “A Dance With Dragons,” was published, the series’s sixth book, “The Winds of Winter,” still doesn’t have a publication date), or between seasons of the show — during which time the intensity of this unceasing, exhaustive speculation only ripens and intensifies. For years, fans obsessed over such mysteries as the possible lineage of the bastard Jon Snow, one of the main characters, forensically marshaling textual evidence in support of the theory (recently confirmed, at long last) that Snow was not a bastard and, in fact, might be the rightful heir to the Iron Throne.

The cumulative effect of all this activity has created a meta-layer, or perhaps a para-layer, a kind of atmosphere that exists above, next to, under and all around the fictional world created by Martin. This para-layer doesn’t actually change or otherwise affect the canon: It is crucial to the integrity of both the fans and the author himself that the boundary between the two is impermeable — there is no feedback loop, and even some of the readers refer to their contributions as “fan labor.” Theories are just that: theories, until they’re proved correct. Martin is the creator, we are the fans, and we rely on him for underlying text that is coherent and internally consistent, unchanging and unchangeable. And this is the way we want it. For one thing, it’s more fun to argue about theories when you believe that there is objective truth. I’ve read the books, and books about the books, and watched the show, and read recaps of the show, and listened to podcasts about the show and gone deep, deep down Reddit holes, discussion threads that start at the level of trivia and descend into minutiae. None of this would be possible with a lesser series, one without the complexity and consistency to support all of this geekery. In fact, this para-layer is essential to both contemporary fandom and “ASOIAF” in particular: The two domains, canon and fanac, validate each other, strengthening the power of each and improving the structure as a whole.

Sometimes this validation happens in tangible ways: Martin is adept at rewarding true fans. When he is visiting a city for a convention, he makes it a habit to go for a drink or a meal with the local chapter of the Brotherhood Without Banners (a multinational fan collective named after a group of characters from the books). At August’s Worldcon, he threw the after-party he has hosted on and off for more than four decades, where he gleefully danced to Daft Punk, mingling with fans, artists, editors and fellow writers.