This text book starts with general entomological issues, surveying the significance of insects, their internal and external structure and how they reproduce, develop and sense their environment. Key features in the success of insects are explored in a phylogenetic interpretation of their evolution. Major themes in insect biology follow: the ecology of ground-dwelling, aquatic and plant-feeding insects, and their social, predatory, parasitic and defensive behaviour. Special consideration is given to insects in medical, veterinary and agricultural science, and to pest management. The traditional order-by-order arrangement of other texts is replaced by a systematic synopsis of each insect order at the end of the appropriate ecological/behavioural chapter. The theoretical framework of cladistics and current evolutionary and behavioural theory underlies the text. Over 200 beautiful drawings of insects, many as seen under natural conditions, will encourage the rewarding study of entomology, whether as a vocation or as a hobby. This book is suitable for students contemplating entomology as a career, and may be used as a principal text for higher education courses in which the study of insects is prominent. These range from mainstream entomology to agricultural science, forestry, zoology and medical and veterinary science. This book should be of interest to senior undergraduates reading entomology modules in biology courses; postgraduates needing more background information.