Editing Core rule book

 A core rule book is typically the first book in a Role-Playing Game system that is released. <br>Within its pages, a reader would find the basic rules, often later expanded in expansion books<br> or splatbooks, some basic setting information, character creation rules and sometimes brief <br>narratives to set the style and feel of play one might expect.

  Sometime the core rule book is broken up into two or three books, normally split between a book <br>for players, a book for the DM/GM/Referee of the game and if there is a third book, that is <br>normally a book of adversaries for the PCs to have conflicts with.

  An example of this would be 2nd Edition Advanced Dungeons & Dragons game, which was originally <br>composed of the AD&D 2e Player's Handbook, the AD&D 2e Dungeon Master's Guide and the AD&D 2e Monster Manual.