I guess first I should say I have not yet read the Grisha trilogy, which was the series that introduced this world. This may be of interest to people wondering if they need to read it first, and I can firmly say you do not. There is a bit of an immediate learning curve to the way the unique magic system works, but it is not hard to follow and gets carefully nuanced as the book goes on. Likewise, the complex factions and cultures are easily understood without denying the richness of their very palpable histories. 
 As for the book itself, it was just fantastically fun. A bit grimmer at times than I usually go wild over, but never too awful. I really appreciate the slightly unorthodox, vaguely flintlock, vaguely steampunk, industrialized setting, in a genre riddled with swords-and-sorcery or else over-the-top steampunk. The various cultures and pseudo-ethnic parallels are a welcome addition to a general stagnation of these factors in one of my favorite genres. 
 Kaz Brekker is perhaps the most perfectly likable unlikable protagonist I have come across. I have seen many authors try to throw out a protagonist along the lines of Kaz, and for the most part I simply find them incredibly disturbing and unrelatable, and/or they just start out over-the-top selfish and bad, but then make a sharp turn into be an idealized reluctant hero. While Kaz has an incredible arc, he never truly stops being the "bastard of the Barrel", from beginning to end, yet I found myself rooting for him constantly. 
 The other characters are also rich and lovable in their own ways. I could go on and on about all of them, but that would make this needlessly lengthy. 
 The humor is well-paced and seems to always land perfectly (and frequently--without the problem of feeling so frequent it's unrealistic, as I sometimes see happen with authors who have a talent for banter). The action and suspense is constant and top notch as well. 
 Off the top of my head I can only think of two very minor "complaints": 
 1. I almost don't understand why all of the main characters had to be in their teens. The majority of them did NOT feel like they were in their teens, even if we were to understand they were thrust into maturity by the awful hardships of their lives. Almost every one of them screamed 20-something or 30-something years old, both in actions the amount of backstory they had. It seemed as if they were written as clearly adult characters, but labeled as teen to appeal to a YA-target. A fairly minor quibble, that maybe has more to do with an unreasonable expectation of the genre itself (I remember being a young teen, and I liked books about adults just as much as ones about characters my age...). 
 2. There is not immediately more available to me!! I was under the impression this was standalone. As I read more and more I kept saying to myself "She has to write another one with these characters!!" Then I felt as if a Grisha Heartrender was wrenching my chest when I got the end! Not quite a cliffhanger, but near enough. Okay, so as far as "complaints" go, "I loved it so much and immediately want more," doesn't really count! That's actually a huge positive. 
 Fantastically fun and unique addition to my favorite genre! 4.5-stars