Because of its peculiar biology, its negative impacts on forestry, and its urticating larvae affecting human and animal health, pine processionary moth has largely been studied in many European countries during the last century. However, knowledge remained scattered and no synthesis has ever been published. Since the IPCC retained the moth as one of the two insect indicators of climate change because of its expansion with warming up, filling this gap became increasingly important. Led by INRA, this book associates 101 authors from 22 countries of Europe, Minor Asia and North Africa, combining all the concerned research fields (entomology, ecology, genetics, mathematical modelling, medical and veterinary science, pest management) in a multidisciplinary approach to understand and model the processes underlying past, present and future moth expansion and to propose adapted management methods. Besides, the major biological patterns of the related processionary species are also detailed.