When worlds collide is a short and to the point document. Its all about using numenera materian in The Strange and the other way around. How to use foci from one game in the other. I would say in this way its more about rules conversion than it is about "fluff" or story reason. Which is covered but just slightly. Over all it was a good purchase since I will be using Numenera in my The Strange games.
[5 of 5 Stars!]