This book is an in-depth look at the natural history of each snake and lizard species/subspecies found in Iowa. Each of the thirty-three species accounts includes a sampling of the common names the species has been known by in the past, the first specimens collected in the state, and a brief history of the early Iowa literature related to the species, along with a complete description and a discussion of similar species, distribution in the state, habitat, behavior, threats, foods and feeding, and reproduction. While readers will be able to identify Iowa’s snakes and lizards through its species accounts, identification keys, and beautiful photographs and illustrations, this book is intended to be more than a field guide. What makes it truly unique is the comparison of historic data collected by Iowa herpetologists in the 1930s and 1940s with data collected by the author, along with James L. Christiansen and others, since 1960. Custom maps show the reader how species’ distributions have changed over time.