A field guide to the 118 most commonly encountered butterflies in the Pacific Northwest - defined here as Washington, Oregon, and contiguous parts of California, Nevada, Idaho, and Canada. The text and abundant colour photographs allow for identification of both male and female adults as well as caterpillars, pupae, and eggs. Author William Neill leads you to the best places to see checkerspots, fritillaries, coppers, blues, and many others, noting which plants attract them.