From the back of the book:
Every campaign setting has a broad section of the map that is simply colored green. This is the wilderness, an unexplored and dangerous area ripe for adventure, but woefully undefined and undocumented. What does this green swath mean, and what can be found there?
Into the Green provides rich detail for four different types of green environments, describing the ecology, terrain, hazards, and resources of each. From tall alpine forests to dark foreboding woods, from lonely and sprawling plains to dense and sweltering jungles, no feature is left out.
Into the Green is designed as a guidebook for both players and GMs alike, providing the resources needed to flesh out a wilderness campaign, and the knowledge needed to survive in one. For the GM, Into the Green details the living creatures and the unique conditions that make up each of the four terrains. Trees, plants, animals, microorganisms, monsters, pitfalls, and climates are all included - the complete cycle of life is defined.
Along with each of the environments are a wide variety of skills, substances, spells, concoctions, devices, gear, and information invaluable for dealing with the specific hazards of the wilds. Every plant tells a story, every creature provides a clue to success, and every monster is a treasure in and of itself.