From publisher blurb: Old School Fantasy Roleplaying: Narrative Rolls provides alternate rules for rolling and interpreting dice results for the classic versions of the most famous fantasy roleplaying game in the world commonly referred to under various abbreviations: Zero Edition, Holmes Basic, Basic/Expert, B/X, Mentzer Basic, BECMI, RC, 1st Edition, and 2nd Edition. Basically, these rules work best with any version before the 3rd Edition of the game.