Other than the play at the begining (which is for adults) the rest of the adventure reminded me alot of a WFRP adventure(not a direct copy mind you just very similar). If your looking for something with that dark cultist sorta feel it wont disapoint. Hopefuly this path will continue to get better.
I'm playing in this adventure path and it seams to really require the PCs to be the heros and do what the NPC leader wants you to do (Sorta like a Shadowrun Mr. Johnson). Its fun but it would work better with a little lead in like maybe your spys from another nation or something.I've gamed with this GM many times so I think its more of the material than the GMing. It probably is one of those adventures with a ton of GM information that never (or almost never) comes out in play.
So this book does exactly what you expect. It gives you all the information you need to run in the time Before and through the night of fire and the long winter. The only reason its not getting 5 stars from me is that there is no option for elves before they got rejected by nature. I was hoping to have everything I needed for a traditional fantasy game but I ended up with 80%+ of what I needed. Still well worth the cover price.
If you liked nWOD or Shadowrun you may love this. It uses a simple dice pool d2 with an improv magic system and a drain like mechanic. The setting is what happened if Rome had magic and then something destroyed everything. The races are different than their D&D counterparts. Nature actually hates the elves after something that happened back in the past. Desolation gives you just enough information to run a Kingmaker (Pathfinder Adventure Path) style game as you explore this world after the night of fire and the long winter.