From the back of the book:
Maybe you know about Deadlands: Hell on Earth, the worst possible future for the award-winning Deadlants: The Weird West roleplaying game. Maybe you've heard about the way the cities of the West and the world were bombed back into the Stone Age during the now-legendary Last War. Maybe you think you've got a handle on the truth about what really happened, about exactly how it all went bad.
Well, you're flat-out wrong.
Lucky for you, brainer, we've got the straight dope right here between two toxic-green covers. The Wasted West is packed full (so full, we had to add 16 extra pages for free!) with new rules for Deadlands: Hell on Earth, including things ranging from witch's spells to power armor, not to mention a passel of new Edges, Hindrances, full-color archetypes, and gear to whip your hero into the kind of waster that actually stands a chance of surviving this post-Apocalyptic age.
There's also "Jo's Journal," a first-hand account of the Wasted West, straight from a Templar who's literally dying to tell you all about it. It's required reading for any wasteland warrior worth his milrats - as long as he's interested in seeing tomorrow.