Wow. This book came out of nowhere and blew me away. It's without question the best new author pickup I've had since I randomly picked up Perdido Street Station, by China Mieville. Half-Made World has a lot of Mieville-esque elements to it, in fact. The novel is 1-part western, 1-part steampunk and 1-part horror, with a solid dash of fantasist, stirred just the right amount.
To an RPG gamer, especially one raised on the tradition of D&D, this book brings an interesting twist to the concepts of Law and Chaos. The fantastic, "half-made" west of the novel is a place where many of the traditional ideas of the western are taken from the realm of the psychological and made real. The world literally gets less real, less "formed" as one moves further west, and the western ocean is a sea of raw chaos from which gods, spirits and creatures form spontaneously.
Contesting for this potential country are the opposing forces of the Gun and the Line. The Gun is represented by the Agents - criminals and anarchists with supernatural powers who rely on subversion, sabotage and stealth. They prefer to avoid direct confrontation, and instead work through cats-paws and unknowing dupes. The chaos and lawlessness of the old west is a clear influence on the Gun, and the fact that their powers are granted directly by the spirit-infused weapons they bear makes the metaphor even stronger.
The Line, on the other hand, is represented by the Engines - massive locomotives possessed of malign intelligence that plot and scheme to spread their railway tendrils and industrial-hell stations across the land. Thousands of Men of the Line serve them - hammered into faceless cogs by the infernal sound of the engines. Black-clad, gas-mask wearing and using steampunk weapons like motor-guns and heavier-than-air helicopters, the Line are methodical, unstoppable and terrifying forces of "progress".
The two forces clash in the "unfinished" west as they both try to capture an old man, once general of the fallen and near mythical Red River Republic - the Camelot of the west, that once defied and fought off both the Gun and the Line, until it was torn down by both Powers. The main characters, a female doctor from the settled north and a rebellious Agent of the Gun, flee from the Line into the far west, where they encounter the last remnants of a fallen history, and things far worse cast up out of the chaos of the western oceans.
The book has great characters, a setting that manages to be both fresh and familiar, and a great mythic-horror-western feel. Lots to recommend here - I haven't heard of Felix Gilman before this, but he's on my must-read list now.