covers all of the 370+ species of shallow-water sea slugs known to occur from Alaska to Central America. In addition to size, range, and habitat descriptions, it also provides information on color variations, eggs, and convenient tips on how to distinguish them from similar species. Richly illustrated with color photos contributed by over 50 of the best "nudie" photographers on the west coast, it is an essential reference for divers, beachcombers, underwater photographers, and anyone else with an interest in this fascinating group.