Kefitzat Haderech - Incunabulum of the Uncanny Gates and Portals is a generic RPG supplement about portals and dimensional gates.
The topics covered are like why are portals cool?, what should I do with them? and how do I build them?
It also comes with a muleload of tables to generate portals and everything related, including PORTATRON, the one-stop-system... [click here for more]