Darwin's World (Second Edition)

Publisher's blurb: Darwin's World 2nd Edition is a revised and expanded version of the GenCon/Ennie award nominated post-apocalyptic d20 RPG. All the new rules are revised for compatibility with the Modern d20 System. This new edition is focused on separating the mechanics from the setting, making Darwin's World the definitive guide to building post-apocalyptic campaigns, whether you are playing in the Twisted Earth or your own preferred post-Fall setting.