From the back of the supplement:
"It was a Dark and Stormy Night...
If you're a traditionalist, you might start your twisted tale out that way, or you could come up with an opening of your own. It's all up to you, Marshal.
The only story you're going to find in this book is yours, the one you and your posse create as you explore the darkest corners of the Weird West together. Marshal's Log is the perfect place for you to keep all the necessary notes on the towns and territories you create for your players' characters to plunder in your Deadlands: The Weird West campaign.
There's space for details on all the heroes roaming your chosen part of the Weird West, plus all sorts of needful things like key extras, villains, and monsters, and the towns your posse's bound to wander through, including places for you to sketch out maps. There are even some blank pages for you to write down the particulars of your posse's saga as it unfolds.
Stop flipping through reams of notes scribbled on odd scraps of paper. Never again worry about remembering that old prospector's name or the details about some abomination's horrific powers. With Marshal's Log, it's all at your fingertips instead.
Simply put, if you're a Marshal, this is one book you can't afford to be without!"