If you're interested in a more detailed survey of rpg theory I highly recommend the recently published "Role-Playing Game Studies: A Transmedia Approach" and sp

If you're interested in a more detailed survey of rpg theory I highly recommend the recently published "Role-Playing Game Studies: A Transmedia Approach" and specifically the chapter "RPG Theorizing by Designers and Players". For a much broader historical work there's also Playing at the World by Jon Peterson. For something more bite sized (and free) check out http://analoggamestudies.org/ http://analoggamestudies.org/