Here are several guidebooks that KPMS members turn to. They all cover a good percentage of Pacific Northwest mushrooms.

All That the Rain Promises and More, by David Arora — A colorful, good-humored pocket-sized guide.
A Field Guide to Edible Mushrooms of the Pacific Northwest, by Daniel Winkler — A laminated folder, suitable for field use, describing about 50 key edible or dangerous mushrooms.
Mushrooms Demystified, by David Arora — Thorough and authoritative, with an emphasis on cascading identification keys.
Mushrooms of British Columbia, by Andy MacKinnon and Kem Luther — More than 350 common species are organized by shape, with an emphasis on common names.
Mushrooms of the Northwest: A Simple Guide to Common Mushrooms, by Teresa Marrone and Drew Parker — Organized by overall shape and features.
Mushrooms of the Pacific Northwest, by Joe Ammirati and Steve Trudell — Nearly 500 of the region’s mushroom species, described and photographed.
Mushrooms of the Redwood Coast, by Christian Schwarz and Noah Siegel — Thorough and authoritative, with fine color photographs.
National Audubon Society Field Guide to North American Mushrooms, by Gary Lincoff — Comprehensive, with more than 700 photos, organized by color and shape.