Mushrooms are among the oldest living organisms on Earth. Over millions of years of their existence, these poorly studied organisms have created and accumulated a large variety of biologically active substances in their fruiting bodies and mycelium, helping them to survive, defend and colonize various ecosystems. The Pacific Northwest is a unique area of our planet, with its own distinct varieties of ancient plants and fungi. Our distant ancestors and Indigenous Peoples knew about the medicinal properties of mushrooms and skillfully used them. Most of modern civilization has lost much of this ancient knowledge and with it, the wonderful healing qualities and medicinal benefits of fungi. In many universities around the world, scientists are currently studying various properties of mushrooms and their uses for medicinal purposes and the possibility of using them in various medical fields. Fungi participate in almost all processes of life; entering into symbiosis with plants and animals. They are an integral part of the human microbiota- a new ‘organ’ of the human body still yet to be fully studied and understood. This book offers information on over 200 medicinal mushrooms that grow in the Pacific Northwest rainforests of North America. This guide will be of much interest to mycobiologists, fungotherapists, phytotherapists, nutritionists, traditional healers, medical students, doctors, scientists, medicine/drug developers, food processing professionals, and generally people who are interested in alternative medicine.