From the introduction: The mini-rulebook contains the basic rules for playing Mortals - the brave men and women who were unlucky enough to be in space when the Rapture came. This book is designed as a quick reference for new players or Game Masters (GMs) that want to print out the core rules for use at a gaming table. The Rapture: End of Days Core Rulebook contains more details and examples of how these rules can be used during the game, and it is strongly recommended that at the very least the Game Master has a copy of that book. Even so, this handy mini-rulebook will give you all the basics needed to play in the Rapture universe.