California and the Western States are rich in abundant and diverse species of mushrooms. Amateur mushroom collectors and mycologists alike will find over 300 species of the region's most common, distinctive, and ecologically important mushrooms profiled in this comprehensive field guide. It provides the most up-to-date science on the role of fungi in the natural world, methods to identify species, and locations of mushroom habitats. With excellent color illustrations showing top and side views of mushrooms of the Western States and a user-friendly text, it is informative but still light enough.