三界宙（Cosmere），台译寰宇，布兰登·桑德森笔下的虚构宇宙，他所写的成人史诗奇幻小说（包括《伊岚翠》、《迷雾之子》系列、《破战者》和《飓光志》系列）全部发生在该体系内。一般而言，读者即便不了解三界宙的情况也能读懂这些作品，但它们之间还是存在一定的隐性关联，建议对界域论（Realmatic Theory）作一了解。 桑德森在书中埋藏了众多彩蛋，就等有心的读者去发掘，这无疑会增添阅读三界宙小说的趣味性。
- God Beyond：God Beyond是某类神祇，本身是很原始、很模糊的概念，其信徒分布于多个三界宙星球，他们相信在阿多拿西和众神瑛之外，还有别的至高存在。
|埃辛||暂无||The Silence Divine|
|纳尔西斯||Endowment||破战者 · 夜血|
|柔刹||荣誉 · 培养||飓光志|
|司卡德瑞尔||存留 · 灭绝 ~ 和谐*||迷雾之子|
|瑟尔||忠爱 · 支配||伊岚翠及其后续 · 皇帝的灵魂|
|First of the Sun||无||Sixth of the Dusk|
When Brandon was beginning writing and trying to get published, he loved gigantic epic fantasy series. He knew, however, that starting with a big series might not be the best idea. If he wrote four books in a series, and the first one didn't get published, he couldn't submit his sequels. He decided instead to focus on standalones and trilogies. Not only would they be easier to market to publishers, but Brandon also wanted people to trust his writing before digging into something bigger.
|I wrote thirteen novels before I sold one. I spent a lot of time practicing and learning, and I love big epic grand series. However, you know, you can't grow up reading the Wheel of Time without loving big series, but advice I heard early on was, selling a big series is actually pretty hard from a new author and if you, for instance, spend your life and you write like six books in the same series, and you send off the first book to someone and they don't buy it, you can't really send them the second book. ... I wanted to expand my chances, and so I wrote thirteen novels in different worlds, all with their own different magic systems and own characters. But secretly I loved the grand epic, and so I started connecting all these worlds during my unpublished era, and telling a hidden epic behind them all that I was setting up for.|
He still loved the idea of a huge epic series, so he decided to create a "hidden" epic to link his novels together. His ideas for this connected universe--the cosmere--came about when he wrote Elantris, Dragonsteel, White Sand, and Mythwalker (which became Warbreaker). Brandon had seen other authors who made a single universe for all their books, like Isaac Asimov, but Brandon didn't like how Asimov had to retcon and shoehorn things together to connect their books. Brandon wanted to do the cosmere from the ground-up, so it would always be consistent.
Some ideas that came into the worldbuilding of the cosmere came from Plato's theory of forms, which contributed to the idea of Realmatic Theory, and the idea of the Physical, Cognitive, and Spiritual Realms. In this, the distinction of what is perceived as "ideal" and what is the true ideal is important: true ideals have much to do with the Spiritual Realm, while people's perception of ideals deals with the Cognitive Realm. Another influences is Spinoza, with the idea that God is in everything. Brandon also incorporated the idea of a "unifying theory of everything" from physics to the magic in the cosmere. All magics have underlying rules, and are derived from a single unified theory of magic.
There is a distinct beginning, middle, and end to the cosmere sequence, and a clear sequence Brandon wants to tell. There's about 36 main cosmere books, and Brandon has three "core" cosmere series: Dragonsteel, Mistborn, and the Stormlight Archive, which are well-planned out. Dragonsteel is the start of the cosmere sequence that will tell Hoid's backstory and, presumably, the Shattering of Adonalsium. Mistborn will have three big trilogies, its last one being science fiction, deals heavily with the cosmere and has travel between the different planets of the cosmere. Stormlight Archive is set in the middle of the cosmere sequence. Generally, the cosmere will not come into the forefront until Dragonsteel or the final Mistborn trilogy, and the final Mistborn trilogy is one of the last cosmere series, if not the last. Brandon has said it will all fit together, and thinks we'll be impressed.
|I hope that people will stick with me for all these books, because I'll do a lot of them. But they will fit together in some really cool ways once they are all done. I think you'll be very very impressed, but that's a while off.|
—— Brandon on the cosmere
At the start of Brandon's career, he wrote cosmere novels in chronological order, but there are books that are skipped, like Dragonsteel and White Sand, some of his earlier, unpublished novels. (Those unpublished novels would need to be rewritten from scratch, much like Brandon rewrote The Way if Kings.) He wanted these cosmere novels to not require knowledge of previous books in the hidden epic of the cosmere. Generally, clues to the cosmere are currently easter eggs, and will not be in the forefront. However, more hints to the greater universe are inevitable, and eventually the worlds will cross over and interact, perhaps in the last Mistborn trilogy.
Hoid, a character who appears in each cosmere novel, is one such easter egg. It is not random where he is; Brandon has said that if Hoid appears in a place, that place is about to be very dangerous. Hoid is doing things behind the scenes, and at some point, we might have Hoid short stories explaining what is doing and why. There are also other people who cross between worlds that eventually Brandon thinks will be much clearer later, once we see those characters more. But for now, they are easter eggs.
Brandon does not feel that the cosmere is restrictive to his writing. Though cosmere novels are intensive, as they require more planning and specific rules (Brandon has continuity editors, like Peter and Karen Ahlstrom, on his internal wiki to keep it straight), he feels that if he needs to take a break, he can just write a non-cosmere novel. Those "breather" novels are used to keep Brandon creatively engaged, and are almost always non-cosmere. If there is a concept he really wants to write but doesn't fit in the limitations of the cosmere, he moves it into a non-cosmere book.
Eventually, there will be an official timeline for cosmere events. There will probably be a cosmere encyclopedia at some point, but not for a long time. It is more likely there will be Stormlight and Mistborn worldbooks first. There will eventually be a Shadesmar map and star map for the cosmere that is released.
Brandon does generally plan out which cosmere hints to give to fans, but sometimes he gives hints on the fly. Usually, fans are able to pry much more than he initially intended to tell.