Naturalists consider the glow-worm Lampyris noctiluca to have declined since World War II in the UK. However, this assertion is mainly based on anecdotal evidence, with few long-term studies undertaken to provide a more robust perspective of the plight of this beetle.

The aim of this book to present the results of a standardised survey of glow-worm distribution and abundance in Essex. It is believed that the survey is one of the first serious attempts in Europe to combine analysis of the distribution of glow-worms throughout a geographical area, with long-term monitoring of abundance to determine whether they are declining across a range of sites.