This was my first Tregillis novel, and after a few aborted attempts (almost DNF) due to the rather odd setup and prose, I managed to finish and like it. Tregillis presents here an alternative reality going back to the 17th century, where Holland managed, via alchemy (magic), to create the Clakkers-- golem-like mechanical beings. Clakkers, or mechanicals, come in various forms, from the ubiquitous servitors found in most upper class households to war machines and even as carriages and ships. Through some arcane process at 'the forge', these beings are animated and given a geas that compels them to obey their master's orders. Yet, as the first chapter establishes, they are as intelligent as humans, making them de facto slaves. Nonetheless, the Clakkers enabled Holland to conquer the world and now, circa 1920s, only the rump New French state (located in now Quebec) has yet to fall under their sway.
Tregillis gives us three main protagonists here. Jax, a mechanical, who starts off as a servitor of a wealthy family in Holland. Beatrice, who starts off as the Talleyrand in New France (e.g., the head spymaster/diplomat), and Visser, a clergyman in Holland who is actually a French spy. Tregillis does have some fun with history here, albeit at not a very deep level. The French are good Catholics (even the Pope is now in New France) while the Dutch (or 'Tulips' as they are called by the French) are of course protestants. Further, while the Dutch are taught (or rather interpellated) to believe that the mechanicals are soulless machines, the French see they as having souls, and therefore as slaves.
Very interesting world to be sure, and I really liked the tech and Tregillis' wry humor at times. On the one hand, this seems to be, or could be, a rather serious probing at the injustice of slavery in any form and contains some sophomore level musings via dialogue on the nature of free will. On the other hand, however, this serious subject matter is eclipsed by the attempts at humor throughout. Beatrice, for example, has a serious potty mouth, and many pages are spend depicting the silly cloths and outfits of the day. Taken together, this creates, or attempts to create, a rather lighthearted alternative reality but one that still deals with some complex and serious issues.
All that stated, Tregillis does give us some good intrigue and various action sequences that move the book along nicely, along with some good world building, and if that is what you are in the mood for, you could do worse. I am a bit uneasy, however, with the rather casual treatment of slavery here. Yes, they are machines magically endowed with intelligence, but the parallels between them and chattel slavery is obvious; it is difficult to find humor in such a state of affairs. All in all, YMMV, but I will go with 3 stars.