Arachnids are among the most diverse groups of terrestrial invertebrates, yet they are among the least studied and understood. This is the most comprehensive field guide to all 68 spider families in North America, with beautiful illustrations of 469 of the most commonly encountered species. Group keys enable accurate identification by web pattern, morphology, and other observable details, and species descriptions include tips to help everyday naturalists identify spiders, as well as their common names, typical habitat, geographic distribution, and behavioral notes. A concise illustrated introduction to spider biology and anatomy explains spider relationships. Featuring 82 gorgeous color plates, this book is an accessible and detailed resource for curious naturalists who want to understand this ubiquitous and ecologically critical component of our biosphere.