“Coast to Cactus: The Canyoneer Trail Guide to San Diego Outdoors” is much more than a hiking guide. It is a field guide too. Written by citizen scientists trained by the San Diego Natural History Museum Canyoneers, it is the new bible for really getting to know and appreciate the county's biodiversity while exploring firsthand. The guide has 245 hikes and an additional 73 hike options making 318 exploring opportunities. Each hike has its own map and symbols indicating the habits found on a trail, a full hike description with mileage, elevation gain/loss, difficulty rating, directions to the trail-head with GPS, trail use, and special features of a hike. There are 525 species of plants, birds, mammals, reptiles, amphibians, and invertebrates that are described in detail. Each hike has a focus on a species or natural/cultural history feature associated with that hike. This book is a learning tool designed to teach the reader what is special about San Diego outdoors. This book is published in cooperation with California State Parks, San Diego County Department of Parks and Recreation, Mission Trails Regional Park (City of San Diego), San Dieguito River Park Joint Powers Authority, and The San Diego River Foundation. This book is like having a Virtual Canyoneer on the hike with you - a trained San Diego Natural History Museum naturalist with you who will teach you what is special about each trail. Purchase of this book supports the mission and programs of the San Diego Natural History Museum.