InfiniteD20 Roleplaying Game Engine is an extremely rules-light, generic, universal, roleplaying set of guidelines. It is a retroclone of a short set of rules provided in a few chapters from an out-of-print 2009 book on extreme roleplaying game mastery by Tracy Hickman and Curtis Hickman. This new expression of the rules is concise, straightforward, and a great way to introduce new players to the roleplaying hobby.