
It had to happen eventually. As Sanderson’s Cosmere books increase in number and complexity, it had to happen eventually that the bigger Cosmere picture would start to take a larger role in new books. If anyone can pull this off well, it would be Sanderson, and The Lost Metal is the most significant proving ground so far that he can manage to continue to tell compelling, intricate, contained stories while integrating those stories more with the Cosmere context. While other books have references to Cosmere activity, this one might be the first one that requires the reader to have some knowledge of that big picture.
What does that mean, in practice? For now, it mostly means that you should at least read Secret History before picking up The Lost Metal, and you would benefit from reading the rest of Arcanum Unbounded as well. While you would probably be able to follow most of the plot without reading either, it would be almost like jumping in without having read the previous books in the second era – sure, you can pull most of the really necessary information from context, but you will understand and appreciate what is going on significantly more with a deeper background.
After so many books in which the broader Cosmere was mostly confined to a few limited appearances that served as sort of insider treats for those who’ve read Sanderson’s other books, the appearance of significant Cosmere elements as major plot points in The Lost Metal was almost as jarring as the time jump from The Bands of Mourning to this final installment in the second era of Mistborn. Several years pass between the last book and this one, and while Sanderson is careful to make that clear from the beginning, and drops numerous allusions to that passage of time, it can still take some time to become accustomed to the change in your own head.
This book was long-awaited, and the reason why I re-read both the first Mistborn era and the other three books in the second era (I will link to all of those reviews at the bottom of this post), and I even read it within a month of its release, despite this review only going live months afterwards (you know how I am about scheduling posts in advance – it made selecting my best books for 2022 additionally complicated). It was…good. Not great, and my favorite book in this second era sequence remains Alloy of Law, but good, and an improvement over The Bands of Mourning.
I am limited in how much I can say about this one without risking spoiling either this book or its predecessors, which I try not to do. What I will say is that the extended epilogue/denouement sequence might be the book’s greatest strength. It is deeply character-centric, and that is probably the strongest part of the whole second era. The second era does some interesting exploration of the world and the magic and the role of the larger Cosmere, but the strongest part of its storytelling, throughout all four books, is the characterization. By The Lost Metal, we have four main protagonists, and they are all wonderfully multidimensional and compelling.
A third era is slated to come next, though I do not know exactly when Sanderson intends to write those. He’s mentioned attempting a Mistborn cyberpunk, and I fully expect that at some point these books will switch over into something with science fiction set dressing (note that I am not saying that they will be science fiction, since even Sanderson’s science fiction is more fantasy than not). Whatever and whenever those arrive, I’m looking forward to seeing where Scadrial goes next.

Mistborn Era One
Mistborn: Secret History (reviewed within Arcanum Unbounded collection)