Boneshaker, by Cherie PriestRead about the other entries on the list.
The first volume of a steampunk alternate history universe called “Clockwork Century,” this is the story of an alternate Seattle, where it wasn’t a massive earthquake that created the infamous Underground, but a massive steam-powered drill invented by a man named Leviticus Blue that ripped through downtown Seattle, uncovering a deposit of “blight gas” and creating an infestation of zombies (and wrecking a large portion of the city in the process). Years later, Blue’s widow Briar Wilkes ventures into the walled city to retrieve her son Zeke, who hopes to find evidence to clear his family’s name. Priest’s stated intent was to give steampunk a “magnum opus,” and Boneshaker delivers with exhaustive worldbuilding, vivid detail, and a ton of atmosphere.
--Marshal Zeringue