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If you’ve been reading Brandon Sanderson’s Cosmere — the shared universe that connects Mistborn, Stormlight, Elantris, Warbreaker, and more — at some point you’ll hear about Arcanum Unbounded. It’s the novella collection. The supplementary material. The thing you read once you’re deep enough in that you want more between the main novels.
It’s also, I should say upfront, not where to start. This is not a book for Sanderson newcomers. It’s a gift for the already converted.
What’s In It?
Arcanum Unbounded collects nine pieces of shorter fiction set across the Cosmere, each with an introduction from the fictional Khriss (an in-world scholar) explaining the planetary system it’s set in. The pieces range from short stories to novellas, covering worlds and characters from across the Cosmere.
The key pieces:
The Emperor’s Soul — the best thing in the collection and, for my money, the best novella Sanderson has written. A Forger named Shai is imprisoned and offered a terrible choice: recreate the soul of the Emperor, who has been left mentally devastated after an assassination attempt, in ninety days — or die. It’s a story about identity, art, and creativity, and it works completely independently of the rest of the Cosmere. If you only read one piece in this collection, make it this one.
Mistborn: Secret History — a companion piece to the original Mistborn trilogy, told from the perspective of a character whose role you discover over the course of the main books. Read this only after completing the original trilogy. If you haven’t — stop here, go read Mistborn, come back.
Edgedancer — an Stormlight Archive novella following Lift, a wonderfully strange character from Words of Radiance. Set between books two and three, it’s essential reading for anyone invested in the series.
Shadows for Silence in the Forests of Hell — a standalone piece set in a world not yet fully explored in the main novels. Dark, atmospheric, and one of the more horror-inflected pieces in the collection.
The Hope of Elantris — a short piece set during the events of Elantris, Sanderson’s first novel. Minor but pleasant for fans.
The remaining pieces are valuable to different degrees depending on how invested you are in the specific worlds they connect to.
When to Read It
The honest answer: after the original Mistborn trilogy and after at least the first two Stormlight books. Most of the value in this collection comes from connection to characters and worlds you already know, and the reveals in Secret History in particular require that the original trilogy is complete.
The Emperor’s Soul is the one exception — it’s genuinely standalone and could be read at any point.
What Works
The quality ceiling is very high. The Emperor’s Soul is genuinely excellent fiction on any standard, not just within genre. Edgedancer is a delightful extended character study. Shadows for Silence shows a different register in Sanderson’s writing — darker and more compressed — that his novel-length work doesn’t often explore.
Khriss’ introductions to each section are a nice touch for deep-Cosmere readers, adding a layer of in-world mythology without being necessary to enjoy the stories.
What Doesn’t Quite Work
The collection is uneven by nature — it’s nine different pieces of different lengths written across many years. Some minor entries feel like exactly what they are: supplementary material.
Rating: 4/5 (for established Cosmere readers; not applicable for newcomers)
Rated 4.7 Stars on Amazon. Buy Arcanum Unbounded here.
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- Words of Radiance Review
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- 11 of the Best Books by Brandon Sanderson
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Check out Sunset In the East — a mind-bending short story collection from Ben Luxon.
