When designing a fantasy setting, the biology of our home planet can provide a wonderfully rich resource for generating a new world and the creatures inhabiting it. But a world creator should not forget the fantasy aspect, or feel restricted to using Earth’s biosphere as an unyielding template.

This system-free RPG sourcebook is designed to help world-builder consider alternatives, provide concepts for them to use, and stimulate ideas and possibilities for their settings. We hope it will help designers pick and choose from the amazing diversity of real life, as well as create new laws of biology to make settings that are as useful and interesting as possible.