From the introduction:

This book presents more than 150 new creatures for Numenera. Most of them are dangerous threats to explorers and settlers alike, and must be driven away or slain. Some are terrible beasts that even a 21st-century human would consider prehistoric. Some are useful not just for meat and hides, but because they can find, produce, or are made of iotum and cyphers, which wrights and other crafters use to build a better world. And some of them are intelligent and civilized, with their own settlements to negotiate with, mysteries to solve, and goods to trade for.