Thanks to NetGalley and Orbit Books for an advance copy!

tl;dr
Powerful world building and a well-defined magic system set the stage for a likable hero and some strong supporting cast as they try to save the world. The front part of the book can be difficult to get through due to pacing and the number of terms.

About
Siyon Velo makes a living collecting alchemy ingredients from alternate planes of existence. It's dangerous, and lawfully dubious, work, but the wealthy alchemists of the city are always willing to pay. Siyon hopes to one day earn enough money to join the ranks of the alchemists himself, but one of the rare items he sells might put an end to that dream - and the entire city along with it.

Thoughts
Reading this book feels like watching someone playing with dominoes. The first half is dedicated to precise and meticulous world building. Characters, laws of magic, culture, politics, geography, and alternate universes are all placed carefully in line, and there's an almost overwhelming amount of things to collate and learn. But then the first domino tips and there's no place to catch your breath as everything falls into place in an fast-paced finale. I confess, it was definitely hard to get through the first part of the book for this very reason. There are a LOT of threads to hold on to. But every single one is stitched into the ending, for a decent payoff. Supporting cast are given a good deal of attention, with some winding up more complex that the lead himself. The author's notes mention Izmirlian was the most challenging character to get right, and I think the extra attention spent on him really shows. He's easily my favorite character of the bunch. The world building is probably the strongest part of the book - details about all aspects of the city and the people in it are thoroughly documented. This book should appeal to anyone looking for a fantasy with some hard world building and alternate plane adventures for a determined young man who finds himself out of his depth.