To scientists and conservationists alike Lepidoptera, butterflies and moths, are attractive species, not simply because many are exceptionally beautiful, with fascinating life cycles, delicate habitat associations, and astonishing interactions with other species, but because they are extraordinarily sensitive to changes in their environment. They act as a bellwether, alerting us to changes that human beings are doing to our environment. This book, edited by John Dover, Martin Warren and Tim Shreeve, is a collection of 31 of the papers presented at the International Symposium: ‘The 2010 Target and Beyond for Lepidoptera’ organised by the environmental charity Butterfly Conservation. The meeting was convened to assess whether the Convention on Biological Diversity and EU targets to halt biodiversity loss by 2010 had been met. The papers presented at the meeting were sobering, butterflies and moths are still in severe decline in countries across the world. As butterflies and moths can be regarded as an above-ground ‘miner’s canary’, then humans have cause to worry if these trends continue. The meeting, and this book, is not all about doom and gloom – yes, it documents problems and highlights very serious challenges, but it also shines light on research that promises to help reverse conservation losses. The book is wide in scope and, for example, includes research on how to improve road verges for rare butterflies in the Netherlands and how agri-environment schemes in Switzerland and the UK can boost butterfly numbers. It shows how studying butterflies in natural bog systems in the USA can help us understand how to conserve butterflies in fragmented prairie habitats and what determines where we find butterflies in the urban landscape of western Australia. The Convention on Biological Diversity is formulating new targets for 2020, and a vision for 2050 - if we are to improve the status of Lepidoptera by 2020 the research documented in this book will help us get there – but the book outlines the huge challenges we face.