The person who wrote the Ars Arcanum in Alloy of Law , is that the same person who wrote the Letter in Way of Kings .
Its not confirmed, but it’s either Hoid, or someone in the 17th Shard. (However, thinking back, I’m not sure if he fully heard/understood the question, and perhaps he was expecting it to be something else. But it seems to me that if he namedropped Hoid, that he may have misunderstood the question, as it seems very likely that Hoid wrote the Letter, I dont think he’d let something slip like that. So i would count this information as rather tenuous.)
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