2004 · コアルール（プレイに必要な最小限）

Gamma World Game Master's Guide

A game master’s guide to a post-apocalyptic world shaped by war, disaster, mutations, and secretive alliances. It provides advice for adapting d20 Modern-based rules, balancing adventure and danger, and planning campaigns from their opening scenes through their conclusion. The book also includes guidance for adding new mutations, technology, and other ideas to an ongoing campaign.