Based on an article in Kobold Quarterly, this takes dwarf cliches up to eleven and creates a species both familiar and alien: creatures born from the earth itself, obsessed with perfection, for whom a punch to the jaw is more eloquent than words. This supplement explores the culture, language, and psychology of this take on dwarves.
Others have complained about unbalanced feats in the WF series. I can't comment on how well or poorly the Pathfinder stats work, since I don't use Pathfinder. Also, if you're fine with plain old D&D/Pathfinder/every-other-FRP dwarves this supplement might not be for you. If, however, you want surly, drunken, perfectionist dwarves with hidden depths and an inhuman mindset, pick up this supplement.