The martian book expands the core game with new armies and races, tripods, grays, red martians and air skiff rules. It is specific to mars and battles with martians. The core rules contain the main rules for the game and includes advanced rules for more experienced gamers. The core rules feature ten army lists, four scenarios and the army build rules. The martian book is not a stand alone book. People play this game in scales ranging from 2mm to 28mm and everything in between. A skirmish version is planned for a later release but the next book is airships and skypirates.