I have it though I can't say I've used it as much as I thought. It's a guide to creating adventures and gives phrase and coins terms that most of us already do anyway. If you have to read a book on how to make an adventure, then I kind of feel like you are lacking something else, but maybe I have just been at it long enough that I do things automatically. Like trying to teach a kid math or something. Actually in retrospect I am not sure why I bought it. Though not useful, it has some interesting parts. 
It helps you develop certain functions of the story that you might not actually have to develop for the adventure to work. This book helps you look into the why's and how's and who's and such.
It takes you through five books divided into chapters they are as follows
Book 1 Milleu Events
   Political and Civil Strife 
            Takes you through different politcal and economic and even religous balances and power such as Spellcasters vs. Nobility or Guilds vs. Merchants and Peasants vs. Preisthood
     Disasters
                 Self explanatory, earthquakes and tornadoes and the like
    Social Upheavel   
                 Deals with things like Revolts and Economic and Cultural decline
    War
            The biggest section of book 1 deals with war on all levels economic, social, how it effects neighboring governments, motivations behind the war such as Assimilation, Holy War, to Resources. Even deals with the opposing army.
         Cataclysms
                Not your typical cataclysm goes into things like Pantheon wars, and Cosmic imbalances
Book 2  Story Roles
     Gives the NPC's specific roles to fill such as Mentor, Ally, Enemy, Competitor, or Hinderer. Each one also has sub-parts that allow you to customize them more
Book 3   Characteristics
    Random NPC generation Tables No explanation required
    Goals and Motivations Talks about why a npc does or is what he does or is. Such ans needs like physiological such as a vampires need to feed or social and material motivations.
    Character Types Gives a ton of types such as Barbarian, Gypsy,Explorer, Scout, Seer, Vagabond. Each type is broken down by Social Class, Common Goals,  and Story Role
Book 4  Plot
This book is divided in the whys and wheres and hows and such. Deals with Story Function, and Story Elements. Also dissects different encounter types, from combative to problem solving. Gives a good range of hook types and how to implement them
This was my favorite section of the book
Book 5  Objective
This gives you a sort of outline to create and adventure. This was the least useful part of the book for me.
All in all I am glad I bought it, but most of the things I already do when creating an adventure or campaign. But still interesting and insightful.
The Seraph of Earth and Stone