Guide for the study of butterflies, both for their own sake and as model animals for exploring basic questions in biology. It covers field-work, project design, laboratory methods, and analysis and interpretation of findings. The first part discusses butterfly biology and five main subject areas where butterflies have proved useful study organisms: biogeography, ecology, behaviour, physiology, and evolution. The second part covers procedures for measuring features and habitats, weather, and micro-climates; mapping landscapes and resources at different scales; recording and interpreting behaviour; assessing population size; and handling live and dead specimens. The last section provides references and a list of sources of equipment and advice.