Knowledge of insect movement, particularly of flight, is crucial to our understanding of the great ecological and evolutionary success of insects. The last 20 years have seen many advances in this subject area. New fields have arisen, such as metapopulation theory, and dramatic developments have taken place in methods of studying movement, as a result of new techniques in molecular biology and radar monitoring. There have also been advances in our knowledge of flight-related physiology and behaviour. This book, which is based on the main papers presented at the Royal Entomological Society’s 20th Symposium held in 1999, brings us up to date with these developments.