This is a guide to the history, ecology, status and conservation of the county's buttterflies. Sixty-two species have been noted since first observations in the early 19th century. Information from many sources is reviewed together with the Hertfordshire Natural History Society's Butterfly Survey field records gathered in the years 1984 to 1986. Many profound changes have occurred in the Hertfordshire landscape and wildlife habitats during the past 150 years with the consequent effects upon the butterfly populations. This book assesses the legacy of these changes and details extinctions, the occurrence of rare migrants, and the increases in some and the ecology and conservation of surviving species.